I beat him yesterday, my strategy was based on what I read in Gamefaqs. First of all, use rain of fire or whatever you prefer to quickly kill the lion (cause it will not do much harm on Cleaver). The boss will only lock you up on his Bolas if you're relatively away from him, now, get REALLY close to him, like REALLY close against his body, if he refuses to kick you, then simply attack him with a strong combo, I used "X X Y Y" wth two swords, but all that matters is that it is strong, quick and you're used to it (so you don't get lost in the middle of the combo), this combo I said managed to even break his defense by the end of the combo, anyway, PRAY that he kicks you, that will stun you, as soon as that happens start abusing the rolling button, get of his atack and roll right back at him and then use the combo on him. I got lucky enough that soon after he changed the sword for the "chain and ball" I got myself a "death song" which allowed me to crucify him, once his health is depleted a B prompt will show up, finsih him ;)
ATTENTION: I fought him on Hard mode, so both stage3s are obligatory battles; however it seems that in lower difficulties the prompt will show up right after the first stage of the battle, and if you press the buttom at the exact time (just like you would in any other boss battle) you'll finish him and skip the second part of the fight. This CANNOT be done in Hard mode. I never tryed to check the veracity of the statement, but it's waht is written in Gamefaqs.