Thread:Commander Ghost/@comment-37453138-20191229134957/@comment-26198742-20200105175317

It's only something that Tamamo No Mae, Nero Claudius, and Nameless/Mumei with Gilgamesh having something Similar in a Manner of Speaking.

The Mythological Mystic Code is Unlocked from a Servant unlocking their Origin within themselves which grants them power on the Same Level as the Ten Crowns possessed by BB within the Moon Cell, it's something they have within the Moon Cell.

It's Something that in a VS Debate could possibly be access at Any Time (Keey word being "POSSIBLY") though in Gilgamesh's Case his Mythological Mystic Code is more or less just Granting him the Power he has when he was Alive (It's why his Outfit is just his Normal Outfit sans the Upper Parts of the Armor) and unlike Tamamo, Nameless, and Nero; His is kept within the Gate of Babylon so he can actually access it at any given time whenever he feels like.

Also Important Note; While Nameless/Mumei and Archer (Fate/Stay Night) are the Same Person, The Latter DOES NOT have access to the Former's Mythological Mystic Code, it is Exclusive too Nameless/Mumei in Fate/Extra and it cannot be included for Archer unless you're specifically using Nameless/Mumei or Composite EMIYA Archer