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I'm tired, but lemme try to explain: A character who originally comes in a more generic/unfinished form transforming or incarnating into something more appropriate to the setting/world and their role.
Wakfu also has something similar, where there's an exclusive class for the tutorial that ends up turning into one of the main classes (which in Wakfu/Dofus overlap heavily with races) upon entering the game proper, and I'm sure there's other examples that I'm not thinking of.
EDIT: Thought of another one. Transformers imprinting on appropriate items in the world to advance from the Protoform stage.
Edited by Nezumi

In Dungeon Fighter Online, the Knight class is composed of the direct creations of some manner of divine being or similar, and they actually incarnate fully into various races as part of picking a sub-class. (So far, Aradian Elf and Terran/Pandemonian half-demon) This feels like it's related to some manner of trope that already exists, but I don't even know what section it would be under, let alone what it is.