I FINALL DID IT!! i've been having some much trouble with him this might seem like a big deal to many of you guys but to me this is the hardest thing i've done and beaten in the game, it was so tense during his last few bars of health i had no potions or ethers left i was just running around dodeging and hoping he wouldn't do his grab move on me but once i defeated him the feels were real (now i just have to defeat the other org members, i hate you Larxene and Marluxia)
also i don't know if this is the general opinion but i think First Xemnas is 100 times harder then Final Xemnas, Final Xemnas moves are easy to predict but if fail to dodge he will punish you HARD but First Xemnas i can never predict what move he'll make especially when he walks slowly towards you. After a few tries i figured out a stratergy which made predicting what move he'll make a lot easier but he is still way harder then Final Xemnas IMO
Also if anyone wants to know i was level 83 on standard mode (because i'm a casual)