Once the battle begins, avoid his tail strikes when they appear from the ground by moving or dodging. When he rears back to yell, press R1 to hang on to the wall and evade his screaming attack. Wait for him to lower his face, then attack his face until he exposes his belly. Attack the belly, then defeat the minions that appear. Avoid his tail attacks again and evade his smashing fist shockwave attack. After he slams his fist into the ground, run up to him and press R2. Then, beat the subsequent quick time event. Attack his belly again, kill another wave of his minions, and avoid more fist attacks. Continue attacking his face until he gets stunned and his tongue appears. Press R2, then beat the quick time event to defeat him.