So for a few weeks there were a lot of arguments about Serpent's identity and I have come here to give you the answer.
mrgreen
It is.............
Nishiki Nisho!!!
emotion_dowant DUNDUNDUNNN
In the manga (Tokyo Ghoul not RE), Nishiki's mask was ever shown. But in the TG official art book, Zakki, (which my friend happened to have) they have a drawing of his mask.
In the manga this is serpent's mask:
And in the official art book of Tokyo Ghoul: ZAKKI
this is Nishiki's mask:
(underneath is Hinami's mask)
(sorry for the bad quality, the lighting was bad)
Serpent is after Torso and this maybe why:
Remember: Kimi has a scar after she allowed Nishi to bite her. And Torso only targets women with scars.
http://the-zoldyck-household.tumblr.com/post/102031699565/tokyo-ghoul-re-serpent-identity-theory