Rixhyln is a traitor to Gremlin society, being a Ghostmane that went AWOL and has been hiding in Emberlight. Doesn't matter if it was for his own good in the eyes of his only friend, Ghostmanes aren't allowed to quit.
The mask can be removed, he just needs it for cleaner air to breathe. He looks a little hideous without it, half his snoot is burnt away so you see his fangs and his gums and stuff all the time. When he has to eat he makes an effort to eat facing away or in privacy.
Assuming he even gets to eat that day. He usually does, but some days he doesn't.

 _plaguebirdd did it