Claire Nunez vs April O'Neil (Trollhunters vs TMNT 2012)
Connections:
Headstrong teenage girls with somewhat of a punk/rock aesthetic who become involved with groups of beings that live underground unknown to most of humanity (Claire with the Trolls of Trollmarket and April with the sewer-dwelling Hamato Clan).
Part of their involvement stems from the fact that they had a close relative taken away from them by a group disguising as humans (Claire having her baby brother taken by goblins working for changelings and April having her father taken by the Kraang). This is shown to cause them great emotional distress, particularly in an episode where many characters suffer from hallucinations showing their greatest fears (In “Where is my Mind?” and “Fungus Humongous).
Both also had people close to them lose their minds (Jim and Splinter), but thanks to their powers, they were capable of undoing this.
They start out normal humans (in terms of abilities) but eventually gain limited powers (Portal creation and psychic abilities). However, these powers are initially not strong enough on their own, making them reliant on other weapons which happened to be intended for someone else (The Shadow Staff which was once Morgana’s and a Tessen that was intended to be for Miwa/Karai).
They each end up getting possessed due to overuse of a particular artifact (The Shadow Staff leading to possession by Morgana and The Aeon Crystal leading to possession by Za-Naron), but after being exorcised, they find that their abilities are greatly improved.