I think Crimvael was a man already. Its implied that his penis is huge too at some point.
Crimvael is intersex not male, which is why they're generally tagged as 1other. From what I remember it's an early plot point that Crim's party assumes they're a guy, and Crim goes along with it to hide the fact that they are not a guy. I think due to being concerned that the guys in Crim's party would try to have sex with Crim, since Crim has both a penis and a vagina.