Azul the Cerulean from Dirge of Cerberus
Firstly, he's about 2-3 times the size of a normal person, secondly, he can turn into an even large and more dangerous bull/lion monster, and thirdly....you don't mess with someone who basically uses the cannon from a tank as their weapon of choice...
And also for some reason after playing this game, i can't stop saying,"Azul, Motherf@#%er! Azul!"...referenced from something else..but still awesome with Azul in the context...