Lesee: Casts spells as 12 sorcerer.
44 HD sounds good to me.
Fire Breath weapons: 24d10 fire damage
Poison Gas: 2d6 con/2d6 con
Stats Maybe like corpse terror: Str 36, Dex 9, Con 26, Int 17, Wis 20, Cha 19
I was thinking maybe a point more dex, and posibly more Con. 30 maybe?