Ugh! I have been trying to kill General Raze for a couple of days now and I can't seem to kill him. I'm level 28.

What I did was:
General Raze wish to heal himself... I didn't remember exactly, but I pull one of the 2 levers (or both?) and run IN the left healingpart! I stay IN and fight for my life (used immediately potions) ... and since Raze wish to heal himself, but I stand IN his way, Raze must first try to kill me before he can heal himself! On that way I can kill him very fast, but his compagnons are maybe a problem to defeat, I know

I wish you all the luck !!

Even if you just stand near one of the regeneration chambers, that will be the one he goes for when his health gets down; if you temporarily deactivate that one using the nearby lever (or block his path with your creature, summons and/or his summoned walking armours), he should not be able to make it to the other chamber (Rush Attack, a bow or magic should be able to finish him off).

General Raze how defeated?

He is about level 29, IIRC, so it wouldn't hurt if you went elsewhere to go up another level or two.
Have you finished off Stone's Flying fortress? If you've cleared a few caves near the start of the fjords, and the path through to High Hall and the harbour, etc, Stone's fortress (north east end of the long island in the middle of the channel to the harbour) would be the next logical place to go; I entered at about level 24/25 and made it to level 29 just before the end.

At the other end of raze's chambers, after you unlock the door, at the other end, not the one that leads to him, theres a portal looking machine, i cant find any switch to turn it on, it looks kind of like one of his regen tubes he gos in except this one has red lava looking liquid flowing threw the tubes an not blue, is it a portal or just for looks or what?