In real life:
A joint decision between WWE and Kane was reached, where it was decided that his character had become stale to the audience.
Coupling that with Kane wanting to shave his head, it was originally Kane's idea to lose the mask. Travelling with the mask and having to go through the necessary make-up and removal of such, caused a lot of unnecessary hassle for Kane. He'd gotten older and didn't need it.
WWE and Kane decided that removing the mask would make life easier for Kane and would freshen up his character.
On TV:
Eric Bischoff and Rob Van Dam decided that Kane was too negative and overly self-conscious. They worked together to implement a Mask VS World Championship match. If Kane lost the match, he would have to unmask.
This obviously backfired as Kane went on a rampage beating jobbers left, right and centre, and inevitably ended up in a feud with Rob Van Dam, and later, the McMahons' (Shane, in particular).
Some say he had a hard time breathing, but his character was beginning to get stale.
Because he lost a match against triple h and the match was if Kane lost he would take the mask off
maybe Kane will take it off
because he had a match which was championship vs mask. Kane lost the match but he still didn't want to take his mask off. so they send ed rob van dam Kane's tag team partner to intimidate him Kane took off the mask but the he chokeslames rob van dam/
Kane hates taking off his mask,SO HE WILL REMASK!
no festus was masked Kane after xpac ripped the mask off in early 2002. then when they decided to take the mask off, Glen Jacobs came back. if you look at the Kane with the half mask thingy, its definetly festus. the gimmick changed so much its impossibe not to see the difference.
He seems to take it on and off now it seems so not sure.
He has now.
Go to youtube and search Kane takes his mask off. You will see that Kane took it off when he was in the ring with Rob Van Dam and Kane chokeslams him.
kane's mask was made from vinyl
Kane lost his match because former Smackdown General Manager Eric Bischauf put Kane in a match against Triple H or Randy Orton it was between them and Kane lost so Randy Orton and Triple H The King Of Kings forced him to take his mask off. But Kane wouldn't so Randy Orton,Triple H and a few other guys began to beat him up but then came former Tag Team Champion RVD (Rob Van Dam) to rescue his former tag team partner Kane he the knocked Triple H down then he gave Randy Orton a Five Star Frog Splash and waited until Kane took off his mask. Kane then took of his mask and there stood a 7 foot tall man with a face uglier than Medusa. And That's the story of the mask taken off by Kane.
Rey Mysterio's mask was inside Kane's bag.
No they are the same person