Also, someone might tell Wyll that devils don't have gender they just assume the gender they think is mostly likely to get the response they are after.
What does their real form look like then? They can assume any form they want? Not all devils can shapeshift? Also mizora is a cambion no?
You're right. I keep forgetting that cambions are the exception to most of the rules of hell.
The Tome of Foes doesn't specify what they look like normally:
To a devil, gender is insignificant. Devils can't create new
life through physical means; a new devil comes into being
only when a soul is corrupted or claimed in a bargain, and
the gender of the mortal that provided the soul is immate-
rial. Devils that represent themselves to mortals are likely
to adopt an appearance (including an apparent gender)
that conforms with what those mortals believe to be true.
Gender (and the assumptions that mortals make about it)
is just another tool for devils to use to get what they want.
Devils that are known to and named by mortals often
accept the gender assigned to them, but they aren't bound
by that label. Stories of the Lords of the Nine told by
mortals might speak of Glasya as Asmodeus's daughter
and Belial as Fierna's consort, but such expressions can't
encompass the complexities of the strange relationships
formed by beings of immortal evil.