Mark of Banka

The Mark of Banka is the Mark of Many Changes. By allowing it to be carved into her body it has granted Akeya the ability to change her form with nearly no restraints. The only real limits are that the form she takes on has to be organic/biological, that it has to be one whole form, and that it has to be a form which can function (something like a dragon, which needs magic but is largely just a functional biological creature is fine, but something like a zombie which can only move because it's powered by magic won't work). There's also a limit in how large Akeya can make herself, but any creature which isn't notably huge is within that limit (in DnD terms, Akeya can't turn into something two size categories larger than herself. No turning into a giant and stepping on people). This ability can both be used for small cosmetic changes and turning into a completely different creature.

Normally turning into a different shape requires quite a lot of magic, and more importantly staying in a different shape requires quite some magic to maintain as well, since most things in this world like their original shape and will try to return to it if forcibly changed. However the Mark of Banka is powerful enough a mark that once placed upon a creature's body that creature can change their form with little to no mana required, and once in an alternate form it does not take any magic to maintain it. Basically the Mark of Banka grants the ability of changing shape as a natural ability rather than a spell or magic effect.