Nothing I've read here is as good as the first name you suggested... for a thrash band, KILL FRENZY is a great name.
...and holy crap, was ArcOfCorinth ever right with these, presumably all culled from the BOVD:
"Pit Fiend
Lifedrinker
Mortal Hunter
Soul Eater
Wight
Devil's Tongue
Love's Pain
Red Fester
Forbidden Speech
Death by Thorns
Rapture of Rupture
Death Grimace
Darklight
Dance of Ruin
Morality Undone
Soul Shackles
Slash Tongue
Heartache
Slow Consumption
Darkbolt
Charnel Fire
Heartclutch
Despoil
Abberate or Abberation
Dread Word
Grim Revenge
Gutwrench
Soul's Treasure Lost
Mindrape
Crushing Fist of Spite"
Of those, I like Grim Revenge best.
I have several names for thrash bands, but as I've not yet joined a band, I'll not share them. Good luck though.