[adamkad1]

Homunculi are a special nature that are defined by their origin, chimera specifically are considered a fusion based race, but given that homunculi are very often artifically created through a shell, I can't see anyone just transforming into one without just dying (Which is the argument for why Dullahans are not selectable in the legend extension menu)

Well, according to peeps on lore channel you can make homunculi with a living being, but they are supposed to lose memory of who they were before. And homunculi can be feasibly created by player characters, dullahan creation is out of that scope though I think.