Black Dragon

well, for the last tier, you're already really tired grinder usually, and the ability? Like, triple fireball? Really KOA? Maybe quadruple-septuple (4-7) fireball...or at least a rare that's like 1/50 that has this ability. Plus people like Dino Monsters and T-Rexes always target you.

Note: if you evolve into KD then it's imperial march time, but KD is really hard to get, another possibility is that the KD keeps it's triple firestorm.

more ability possibilities:

force field: like roar, pushes others away

sinkhole: pulls others in

sinkhole-force field combo: what it's name says is what it is

fireball damage buff: like 5x more

high fly: like the ptero

invincibility for 5 seconds if you reached half health

immune to all negative effects if reached 1/4 health

regen if on fire

regen 1/2 the health taken

regen the damage dealt