Akuma VS Iris Heart is a What-If? episode of Death Battle. It features the return of Akuma from the Street Fighter series and Iris Heart of the Hyperdimension Neptunia series.
Description[]
Street Fighter VS Hyperdimension Neptunia! It's Neutral Evil VS Chaotic Evil as the sadistic goddess battles the mightily powerful Street Fighter Akuma! Who will take glory?
Interlude[]
Wiz: Evil comes in many different shades. Some villains like to be honour-bound, but some just like to be flat-out nasty. Lawful Evil, Neutral Evil, and Chaotic Evil are the three defining types of this character. Today, two of them will go out head-to-head in a no-holds barred clash.
Boomstick: On the Neutral side, we have Akuma, Master of the Fist!
Wiz: And on the Chaotic side, we have Iris Heart, the sadistic goddess.
Boomstick: He's Wiz and I'm Boomstick!
Wiz: And it's our job to analyse their weapons, armour and skills to find out who would win... a Death Battle.
Akuma[]
Wiz: In a world of skilled and legendary fighters from across the globe, there exists none more deadlier than the mighty Street Fighter, Akuma.
Boomstick: Why? Because he's a master of the dark arts! Get yourself strapped in, ladies and gentlemen, because this guy is pretty cool!
Wiz: Akuma - or Gouki in Japan - is a powerful fighter, who was trained by Goutetsu with his brother, Gouken, in the ways of an unnamed martial art, crossing elements of Judo, Karate and Kempo. But Goutetsu also taught another dangerous technique which sacrificed the user's safety for sheer power.
Boomstick: As time went on, Akuma and Gouken naturally argued about the fighting style being taught and how to master it. They then went their own separate ways, with Gouken leaving to start his own dojo and teach the non-murder way of Goutetsu's art, while Akuma stayed and continue to practice it. Which was a good call for him in the long run!
Wiz: In order to master this dark technique, Akuma had to give in to a dark power called the Satsui no Hado, literally the Surge of Murderous Intent. Here, he closed off all compassion for others and realized that his capability could be expanded further. So, he left Goutetsu's guidance and trained on his own, gaining more power and a lust to fight to the death, courtesy of the Dark Hadou consuming him.
Boomstick: After what I can only assume is a lot of fighting and slaughtering, he finally came back to Goutetsu and challenged him to their own personal Death Battle to prove that he had surpassed his master. He even used the dark technique he wished to master to kill his... erm... master. But at least Goutie died happy to see Akuma at such a high level, and Akuma even got those beads around his neck!
Wiz: However, Gouken was... less than pleased. Years later, Akuma fought Gouken with the young Ryu and Ken Masters as spectators. After an intense battle and plenty of arguing, Gouken defeated him, but spared his life. Which would prove to be his undoing in the next encounter when Akuma used the same dark technique to supposedly kill his brother.
Boomstick: Oh, I remember now, he can finger-paint!
Wiz: Thanks to the Satsui no Hado, Akuma is a walking weapon, nearly ten times stronger than any other Street Fighter in the world.
Boomstick: And when you consider Street Fighter's line-up, that's an accomplishment in itself!
Wiz: Akuma has plenty of powerful moves at his disposal. Such as the Gou Hadouken, his own take on the iconic projectile attack, which can be amped up into the almighty Shinku Hadouken. He's also capable of firing multiple Gou Hadoukens at once, including in the air as the Zanku Hadouken.
Boomstick: Anyone who hasn't tried to fire a Kamehameha will likely have tried to fire a Hadouken. Don't lie - we've ALL tried it at least once!
Wiz: There's also the Goshoryuken uppercut attack, which is capable of launching the victim sky high. He also has a Hurricane Kick and the Hyakkishu, otherwise known as the Demon Flip.
Boomstick: He can teleport short distances, even passing through attacks along the way, and he also has a powerful special move known as the Kongou Kokuretsuzan... Hey Wiz, did I get it right this time?
Wiz: *Rummaging through some papers* Actually, that's pretty much spot on.
Boomstick: I knew I'd get there eventually! Well, in any sense, Akuma unleashes a ground attack that pretty much fucks anyone who gets caught in it up! It was even capable of destroying a friggin' mountain!
Wiz: But Akuma, being a master of the Dark Hadou, has one painful move in his already deadly arsenal.
Boomstick: When he really needs to finish his foe, he will utilise the dark technique taught by his master, the Shun Goku Satsu, or as it's known to us common folk, the Raging Demon!
Akuma demonstrates the ability on his unfortunate opponent.
Wiz: This attack is not a physical attack by Akuma, but rather an attack that turns the sins of his foes against them, destroying and outright eradicating their soul. It was this exact attack that Akuma used to kill his master and attempt to kill Gouken with.
Boomstick: Talk about a horrible, HORRIBLE way to die!
Wiz: Indeed. Akuma lives for one thing - fighting. Akuma will wander the world endlessly looking for a worthy opponent to challenge him. He's fought and defeated many foes, only being defeated to the likes of Gouken in the first encounter, and later Ryu would prove to challenge him from time to time. However, it's important to understand that Akuma requires complete control over the fight to be effective - he is always attacking and always on the move, offering an offence-heavy fighting style. And because of his high power, he has to constantly hold back in order to give his opponent a fighting chance. However, the Dark Hadou can be taken one last step further into a further stage.
Akuma transforms into Shin Akuma.
Boomstick: Enter Shin Akuma, a badass-looking higher form with even more badass moves! His strength increases to its full extent in this form!
Wiz: As Akuma is at full power in this form, he does not hold back at all, making for a fighter with enormous power! ...The only downside to this deadly form is that Akuma would only consider going into this form if he is fighting a worthy enough opponent to not hold back on his power. Which most of the time, he doesn't get to fight.
Boomstick: But worthy or not, if you find yourself in a fight with Akuma, you'd better hope he doesn't unleash his dark skills on you! There's a reason he's called Master of the Fist!
Akuma: I am Akuma, and I will teach you the meaning of pain!
Iris Heart[]
Wiz: True evil is something cruel. Something unstoppable. Something dreadfully deceiving.
Boomstick: A perfect description for the goddess dominatrix known as Iris Heart!
Iris Heart arrives on the scene.
Boomstick: Iris Heart is a sadistic woman with plenty of power. And I presume she's heavily dominant in bed. Not that I'd actually want to find out, because even I know when to respect my limits.
Wiz: Plutia is the goddess of Planeptune in the Ultradimension, a link between all of the many Hyperdimensions.
Boomstick: So do they have some kind of hover car system and all kinds of futuristic knick-knacks?
Wiz: No, Boomstick. This was the 80's.
Boomstick: Oooooohh... so they have ridiculous hairstyles and rock out on key-tars while quoting He-Man?
Wiz: ...No.
Boomstick: So what the fu--
Wiz: Anyway, Plutia is innocent enough in her base form, if not a little difficult to read in terms of thought and emotion, though she is a considerably good fighter. But when she gets angry enough, she will transform into her HDD - her Hard Drive Divinity - Form, Iris Heart, arguably the most merciless goddess ever known.
Boomstick: Like Bruce Banner if he was an anime girl!
Plutia transforms into Iris Heart.
Wiz: Turns out Iris Heart is almost the exact opposite of Plutia, being a cruel and sadistic woman who loves nothing more than to torture her victims - friend or foe alike.
Boomstick: Men... women... animals... no-one is safe from Iris Heart's wrath!
Wiz: Her sadistic and outright cruel tendencies makes her a feared woman in the whole world, where even the other goddesses don't wish to deal with her and refrain her from transforming unless it's absolutely necessary.
Boomstick: She's a controller of her own anger and uses it to her dominant needs, even making Noire, a woman who is extremely unruly and won't back down to anything, break completely. *Sigh* Poor lady. Someone ought to give her a hug and some coffee to calm down.
Wiz: ...What is with you today?
Boomstick: I don't know...
Wiz: Regardless, in combat, Iris Heart is a monster - kind of ironic, when you consider the situation.
Boomstick: She's got a lot of moves to torture her victims! Pulse Rush hits eight times and Bow Down lets her step on her foe and rub her heel on them! Then there's Iris Break and Break Edge for moderate damage as well as embedding her katana with one of the elements! And it's even capable of going into snake sword mode with a flick of her wrist, just like good ol' Ivy Valentine!
Wiz: Fighting Viper is her signature move, allowing for an electric attack with her sword, and Drive Stab virtually seals off one of the opponent's moves, and she is capable of provoking the opponent with Verbal Abuse.
Boomstick: But her highest power attacks are her EX and EXE Skills, like the Super Thunder Blade, a move so powerful it's capable of paralysing the opponent! But T. Blade Kick is her most devastating move, with thunderstorms and lasers for flair!
Wiz: She can also fly and create a barrier, as well as transform into a stealth wing with her Final CPU transformation.
Boomstick: Yeah, one that's capable of blowing up THE WORLD with Neptune's power!
Wiz: Where'd you even hear that? Regardless, Iris Heart is a powerful goddess. She's invoked fear into the other goddesses, overpowered Arfoire and, with the help of a past Rei Ryghts, overpowered Rei's evil energy.
Boomstick: What kind of Back to the Future stuff was that?
Wiz: However, despite her power, she does tend to focus more on torturing her enemies rather than kill them. In fact, she even heals them sometimes so that she can repeat the vicious cycle. Not to mention she does seem to have a fair bit of arrogance.
Boomstick: But she can prove to you why she's so full of herself in a second! If you find yourself in a dark alley alone with Iris Heart, don't bother running - you're pretty much already doomed!
Iris Heart: Me? I'm Iris Heart. Don't worry about memorizing it. I'll carve it into your body for you!
DEATH BATTLE![]
AgentHoxton[]
A sunny day was dawned over Planeptune. A gorgeous blue lake shone in the sunlight in an empty field. And stood over this lake was a figure in a dark gi and a matching dark robe. He stared across the lake in silence, before his attention was brought to a sound in the sky. He looked up. While his face was shrouded in the cloak's darkness, it was clear that he raised an eyebrow as if to say "What is that?"
Up in the sky, an object flew across the lake and out of sight in a forest clearing. A few seconds later, an impact was heard. The mysterious figure looked at where the shape had gone. He knew what it looked like. It was a person. Perhaps it was a possible opponent for him? He decided to leap off the rock and go and investigate himself.
Meanwhile, in the impact site, a young girl was trying to dust herself down following the nasty fall from the sky. This was the young girl, Plutia. Approaching her from the shadows of the forest were two men. One of them looked like an athlete - a boxer, to be specific. The other was wearing a mask and wearing a clawed glove - in his other hand was a piece of paper. These were Shadaloo's finest: Balrog the Boxer, and Vega the Assassin. Plutia stood up and realized the men were approaching, and smiled sweetly.
"Hello, how can I help you?" She asked. Balrog looked at Vega and smirked. Vega stepped forward and presented the paper to Plutia - an official looking form with a Shadaloo logo on the top.
"Are you the goddess of this region, señorita?" Vega asked her, handing the form to Plutia. Bison had wanted to gain authority controls over the landmasses of the Ultradimension, in an attempt to gain even more power. Plutia stared at the form before looking at Vega.
"Yes, I am. Why do you ask?" Plutia asked. Balrog then stepped in front of Vega, ready to explain.
"See, Bison is offering more power to your region. All ya gotta do is sign that form to hand ownership of this Planeptune place to Bison, and things'll be fine." Balrog explained. He looked over his shoulder to Vega, who nodded slightly. Plutia stared at the form more before starting to get angry.
"This is my region." She snarled, scowling at the two fighters before her. Balrog and Vega looked at each other, before Balrog slipped in a smirk.
"Not for too long. Bison will want your region soon. By force if needed." He shot back. Plutia got even angrier at this remark, clutching the paper tightly.
"You don't even believe me? Well, I'll show you just for that..." Plutia growled, before transforming in a bright light sequence. Before long, there was no sign of the young girl Plutia, but it was now replaced by a tall woman with cybernetic-looking wings behind her, and a lot more of a crueller smile on her face. This was not Plutia. Instead, it was the CPU of Planeptune, Iris Heart.
Balrog and Vega looked on in confusion before Iris Heart took the paper and shredded it with her hands.
"Perhaps now I'll take you two and record myself brutally torturing you in the most gruesome way I can imagine. Then I'll send the video to this Bison person and tell him to shove his proposed plan up his--" Iris Heart was in the middle of explaining her plan before she noticed someone approaching from behind the duo. Balrog and Vega looked at each other before turning around to spot the mysterious figure from the lake approaching them slowly. Iris Heart tilted her head. Was this figure in league with this duo? Who was he, anyway?
"State your business." Vega growled, pointing his clawed hand at the stranger. The stranger's eyes suddenly glowed red, before he reached up and pulled off his cloak, revealing his face, showing his red eyes and hair. This, combined with his black gi, meant only one thing - the arrival of the mighty Street Fighter, Akuma. He stared at the duo before him.
"I have business to deal with in this woman." Akuma growled at Vega in response. "And if you know what is good for you, you will back down." Vega and Balrog both snorted.
"As if." Balrog shot back. "What are you going to do to us, anyway?"
Akuma got angry at this, and shrouded himself in a dark aura before rushing towards Balrog and Vega. Iris Heart watched as he approached them. Suddenly, everything got dark and the sounds of... something... hitting their marks was heard, with white dashes all over their location. Before Iris Heart could even realise what had happened, Akuma was now facing her. Balrog and Vega laid behind him, both of them dead through Akuma's Shun Goku Satsu. Iris Heart was somewhat intrigued.
"Well now, aren't you a brash person?" She grinned maniacally. Akuma stared at her with a stern expression. Iris Heart then wandered a little further away.
"I was going to ruin those two goons... but I suppose you'll have to do instead. So before I stomp your pathetic face into the ground, I might as well ask for your name." She continued. The man's response struck a nerve in the goddess.
"I am Akuma, and I will teach you the meaning of pain!" He answered, slamming his foot into the ground. Iris Heart cocked an eyebrow up before laughing a little.
"How cute. I wrote the book on pain." She mused, playing with her sword a little bit and eyeing Akuma with a deadly stare. Akuma cracked his knuckles, ready for battle.
"Then I challenge you to fight me, CPU Iris Heart. Perhaps then we can determine who knows best." Akuma offered, getting into his fighting stance. She may not be worthy enough of an opponent to witness his full power, but perhaps he can get a good fight out of her? Iris Heart grinned at Akuma when he gave her this challenge.
"Oh, Akuma, I thought you'd never ask~..." She purred evilly as she set her sword to her side, floating off of the ground.
FIGHT!
Iris Heart flew forward and thrust her katana towards Akuma, who jumped back to avoid the blade. He then jumps up with a Demon Flip and thrusts his leg out, missing Iris Heart's legs by a few inches. He then punched the goddess in the stomach, following up with two punches to the face before knocking her into the air with the Gou Shoryuken. As she fell down, he fired a Gou Hadouken at her before striking her four times with his Tatsumaki Zankukyaku, ending the combo.
"You aren't proving your worth!" Akuma growled. Iris Heart got angry at this.
"Are you tempting fate?" Iris Heart asked him, before turning her katana into a snake sword and lashing it at Akuma. Akuma got slashed once before blocking to try and minimise the damage from the other strikes. Iris Heart then lunged at him, which Akuma jumped back again to avoid. But this time, Iris Heart got behind him and kicked him in the back before using Pulse Rush. After the combo, Akuma fell to the ground, and Iris Heart landed nearby. She then lashed her snake sword out like a whip at the downed Akuma, but he rolled back just in time to avoid it, grabbing her and throwing her to the ground.
"I've seen abhorrent evil before in the likes of that dictator..." Akuma spoke. "You and him are much alike... in terms of atrocity!" Iris Heart got to her feet slowly, eyeing Akuma with a death glare.
"You should have played smart and not fought back, you filthy maggot." Iris Heart shot at him, before setting her sword back into its whole form and imbuing it with fire, lunging at Akuma again. This time, her attack was more successful, getting three solid sword swings on the Street Fighter and knocking him into the air. She flew up and kicked him in the stomach, launching Akuma into the ground. Iris Heart landed and used Bow Down, stomping her heel on Akuma's stomach.
"Now then. Let's see how tough you are..." Iris Heart grinned. She grabbed Akuma by the leg and raised him over her head before smashing him down on the ground. She laughed maniacally as she raised him again and smashed him down again. But before she could slam him down a third time, Akuma grabbed Iris Heart's shoulders, hopping over her head and somersaulting to throw her over him, further away. Iris Heart responded by attempting Fighting Viper, but Akuma used his teleport to get out of the way of the attack. Iris Heart was starting to get irritated by Akuma's resistance, and decided to bring up some Verbal Abuse.
"I'll be sure to leave you dead on the streets after I abuse you. And no-one will ever stop to help you. You'll die alone with no-one to love you." Iris Heart spat at him. Akuma didn't seemed phased at all by what she had said, just cracking his knuckles again.
"Your threats are almost as pathetic as your existence!" Akuma responded, before leaping up into the air and meeting Iris Heart with a solid kick to the head. As she got knocked back, Akuma used his teleport to get behind her, meeting her with another Gou Shoryuken. As Iris Heart landed on the floor, Akuma decided to use his strong attack, the Kongou Kokuretsuzan. He charged up his fist and then punched the ground, unleashing a massive-damaging shockwave that knocked Iris Heart back into the air. This time she stayed there as she hovered above him.
"You're just being lucky." Iris Heart remarked, before imbuing her katana with electricity again and shooting out her katana in snake sword form, slicing Akuma across the chest and making a cut into his gi, showing the scar of the sword strike. She then got back to the ground again, punching Akuma in the face before using Iris Break to damage him and floor him. She then walked up to Akuma, picked him up and Drive Stab on him, stabbing him in the side of his waist. Akuma pushed himself off of the goddess and performed his Gou Hadouken...
...nothing came out.
Akuma got back into his fighting pose. The move had worked fine before. What did he do wrong to cause it to not work? Iris Heart grinned at his realization.
"You won't be able to use that little move of yours for a while..." Iris Heart told him. Akuma stared at the goddess, taking the information in.
"I won't require that to beat you!" Akuma declared, rushing at her again. Iris Heart created a barrier around herself, which Akuma attacked with most of his strength as Iris Heart idly watched from within.
"Oh, look at your pathetic efforts." Iris Heart taunted as she watched Akuma attack the barrier tirelessly. "All brawn and no brain, just constantly fighting to prove how heartless and stupid your motives are--" She would have continued, if not for the fact that Akuma, after all his other attacks failed, used his Kongou Kokuretsuzan again to shatter the barrier. Iris Heart stumbled back before hovering off the ground to regain her balance.
"Well now..." she said. "At least you're not completely useless."
"Tch." Akuma spat.
She set her katana back in whole form before using it to slice at Akuma again, who jumps into the air to avoid it, firing his Zanku Hadouken at her. Iris Heart was barely phased by the energy blasts. She then tried her Super Thunder Blade, but Akuma teleported out of the way, causing the attack to miss. Akuma then leapt at Iris Heart again, knocking her into the air with Gou Shoryuken, before jumping up and using his fists to slam the goddess into the ground. As Akuma landed, Iris Heart got irritated.
"You just WANT to die, don't you? Well, I'll make sure of it now!" Iris Heart barked, kicking Akuma as she was utilising her T. Blade Kick. The skies darkened and thunder began to boom. Suddenly, a lightning bolt struck Akuma, phasing him temporarily, before Iris Heart blew a kiss at the Street Fighter, launching four powerful lasers his way. They all exploded as they hit him, kicking up a cloud of smoke. The skies cleared again as Iris Heart looked on. There were no signs of Akuma from within the smoke. She grinned and toyed with her hair.
"I told you not to mess with me. But I suppose everyone has to make me do it the hard way..." Iris Heart gloated. She felt she had won.
But then a red glow emerged from the cloud and a shape emerged, leaping out of the cloud. Akuma then landed with his fist down, creating cracks in the ground. His clothes were visibly torn more than earlier, and Akuma's skin was even showing scratches and bloodstains. But Akuma wasn't ready to quit yet. Iris Heart was disappointed.
"I'd have thought you'd have gotten the hint by now." Iris Heart remarked. Akuma stared at her, intent on finishing the match.
"I am never down until a worthy opponent puts me down at my full power." Akuma answered. "Now come! Continue the fight!"
"I think you'll find I will be the only worthy one!" The goddess grimaced before charging at Akuma again, her sword embedded with electricity this time. Akuma dodged the coming sword strike and grabbed Iris Heart by her hair, throwing her over his head. She then brought the sword into snake mode and lashed it at Akuma, who grabbed the tip of the blade in his hand. He yanked, pulling the goddess towards her, before giving her a roundhouse kick, causing her to be knocked back and dropping her katana. Akuma picked up the sword, inspected it, and then rushed at the goddess with it in hand, stabbing her clean through the stomach with it. Iris Heart coughed up blood and her stomach began to bleed as Akuma pulled the sword out of her stomach and snapped the blade over his knee, breaking the sword. He then walked off as Iris Heart got to her knees.
"You were never worthy of seeing my full strength. Not with your actions." Akuma spoke as he walked away. Iris Heart looked on. She felt angry. She wanted this man dead. Deader than dead, in fact. She decided to use her Final CPU transformation, and transformed into her stealth wing form after a bright light flash. Akuma looked back in confusion before getting struck by the stealth wing, and being carried up far into the air. After a few seconds of ascension, Iris Heart in her stealth wing form began to plummet, intent on driving Akuma into the ground at full force. However, a sharp red glow appeared in the Street Fighter's eyes. He wasn't quite ready to be defeated yet, pushing himself away from the foreign form. He used his Tatsumaki Zankukyaku to knock away the stealth wing before charging a powerful energy attack.
"Shinku..." Akuma chanted as the stealth wing Iris Heart attempted to strike him in free-fall again. He needed to time this just right.
"...HADOUKEN!" He finished, unleashing a powerful energy blast that knocked the stealth wing form down and pushing him further back. The Shinku Hadouken smashed the stealth wing against the ground, bouncing off before a bright light cued her transformation back into her goddess form. She was battered, bruised, but above all else, she was pissed. Akuma landed shortly afterwards to face her yet again.
"You are going to DIE!" Iris Heart yelled in bloodlusted anger as she rushed at Akuma. She was going to beat this man, through beating him to death with her own hands if she had to.
"We shall see about that!" Akuma barked back, getting into a pose that surrounded him with a familiar-looking red aura. He had activated the Shun Goku Satsu. He then dashed towards Iris Heart as well, intent on meeting her head-on. The two fighters raced at each other at high speed, but of the two's attacks, Akuma's struck first.
For Iris Heart, reality seemed to break before her eyes.
Akuma had frozen in place. As did the scenery. It was as if the whole world was frozen in time. Iris Heart looked around in slight confusion as the world began to darken around her. Before long, she couldn't see anything. Nothing but the red glow in Akuma's eyes looming over her.
She didn't know what was going on. What did this man do to cause this to happen to her? Before she could figure the answer out, a white orb appeared before her. A memory. A memory, in fact, of her abusing the rat Pirachu.
"Oh, I remember that." Iris Heart mused to herself. "How fun that was~..." She chuckled to herself... but then her chuckle was cut off by the orb turning into a white line that slashed through her stomach. As if it penetrated her very soul.
"Wh-??" Iris Heart spat as a small amount of blood poured out of her mouth. She then saw another memory orb. One of her... moment... with Noire. This time she didn't comment, just watching what would happen. She felt the sharp pain again as the memory turned into a slash that cut through her stomach and penetrating her soul, much like the last one.
Iris Heart tried to resist her pain. Was this what Akuma used on those two men before the fight? She then saw multiple orbs appear, all with unique memories of her abuse of others.
She realized where this was going. And the realization was painful. Suddenly, practically everything went pitch black as Iris Heart yelled out.
The world was brought back into view as a huge smoke cloud fogged the view of the fighters. But within the smoke, the bright light of Akuma's iconic heaven kanji shone brightly, with Iris Heart lying dead on the floor courtesy of the Shun Goku Satsu, transforming back into a dead Plutia. Akuma stood with his back to her before he spoke out again.
"But by the end of the day, it was you and your sins that failed your chances of putting me down." He declared, not even turning around to look at his fallen adversary.
And with that, he grabbed his cloak that had blown by in the breeze and put it back on before walking away, hoping that someone else in this strange land could offer an even better fight.
K.O!
Results[]
Boomstick: ...Well... Didn't see that one coming.
Wiz: This was a very close match. Iris Heart may be powerful and durable enough to stand up to Akuma's strength and speed, but Akuma's power and connection to the Dark Hadou was enough to let him overcome most of Iris Heart's attacks.
Boomstick: Akuma's proven time and time again he can compete with the best of the best, and his strength is leagues above a lot of Street Fighters! Iris Heart may have broken unruly characters like Noire before, but Akuma's a different beast altogether with his lack of emotion. Not to mention aiming to torture your foe isn't the best idea against someone who is more focused on fighting and killing you!
Wiz: With Akuma's strength and speed against Iris Heart's durability and stamina, there was really only one factor that could permanently see off Iris Heart effectively through bypassing her durability altogether - the soul-killing Raging Demon.
Boomstick: It tends to be Akuma's ace in the hole, doesn't it? And before you ask about why Drive Stab didn't shut it off - well, it was only a CHANCE to shut it off, and there are a lot of things in Akuma's move-pool, making it unlikely that the Raging Demon in particular would be targeted through RNG!
Wiz: Remember, the Raging Demon turns the sins of the victim against them and attacks their soul. When you look at Iris Heart, it's easy to know that Iris Heart has committed many atrocities. Abuse, torture, and even implied rape of Noire, which would account for quite a hefty amount of sins. Meaning Akuma had little trouble turning Iris Heart's deadliest asset into her worst weakness.
Boomstick: Guess Iris Heart, of all people, was just taught her "soul" purpose in life!
Wiz: The winner is Akuma.