...what's the usual scale death metal musicians write their music in? I'm thinking more on the lines of Bring Me The Horizon (and yes I know that's deathcore) and maybe like Cannibal Corpse.
I write the music for my band and I usually do conventional metalcore scale structure of D minor and our sound's like As I Lay Dying at the moment but I wouldn't mind crossing genre and putting in a few death metal riffs.

Chromatic minor I'd say. though it's hard to define the key of a deathcore/death metal song
but chromatic,diatonic and pentatonic is used alot along the chuggachug and tremelofpicks