KH Birth By Sleep Final Mix (1.5 + 2.5 ReMIX) - Terra-Xehanort boss fight (Terra's story)
12[WARNING: THIS VIDEO CONTAINS SPOILERS FROM THE TERRA'S SIDE OF THE MAIN STORY OF KINGDOM HEARTS BIRTH BY SLEEP]
This video features the final boss fight of the Terra's side of the main plot of Kingdom Hearts Birth By Sleep against Terra after being possessed by Xehanort (a character usually referred as "Terra-Xehanort" or even "Terranort" by the fans). The player fights the boss in the form of the Lingering Will, Terra's suit of armor as it's being animated by his wielder's mind, which was first seen in Kingdom Hearts II Final Mix as a bonus boss. For all intents and purposes, the Lingering Will retains all the equipment, stats and abilities the player achieved on Terra up to that point.
Note that this video was recorded while playing Birth by Sleep on its Final Mix, 2.5 ReMIX version from the 1.5 + 2.5 ReMIX compilation for the Playstation 4 and on Standard difficulty. I was also on my Playstation 4 Pro.
Terra-Xehanort is widely considered by many to be the hardest boss fight from Birth by Sleep, topped only by the resident bonus bosses and the stronger version of the boss you get to fight as Aqua in the Final Episode. The main issue people seem to have is that Terra-Xehanor is that he's an insanely aggressive boss who pursue you relentlessly through the whole fight as he dishes out very long combos of attacks almost impossible to escape from and which have a fair chance at killing you in one fell swoop. It also doesn't help that Terra-Xehanort basically can't be targeted by your finishing moves or your most elaborate, multi-hits commands, as he will dodge them flawlessly each time and smack you around in retaliation. As the battle goes on, the boss will also start casting Cure spells on himself, further dragging on the whole thing.
As shown in the video, the safer way to face Terra-Xehanort is to abuse Terra's Counter Hammer command to punish the boss aggressive A.I.: many of your enemy's attacks can be countered with a bit of practice and at this point in the game the Hammer can dish out a nice chunk of damage and fill up your finisher meter nicely (and performing a finishing move will make your invincible for some precious seconds).
The two limit attacks Terra-Xehanort will start to cast at an allarming rate towards the end of the fight deserve a special mention, however:
1) Meteor, which will summon several small meteors from the arena and then have them all thrown at your character for massive damage. Since the meteors will damage you even if you are caught up in their summoning location and will basically one-shoot the Lingering Will if they connect, your safest bet here is to initiate a shotlock action of your own and hope to become invincibile for Meteor's whole duration as you also deal damage to the boss. The only issue with this strategy however is that the boss will keep teleporting around during the attack's preparation, making maxing out your attack difficult.
2) Ultima Cannon, which will summon a huge ball of energy in your general direction. Unless you have specific commands able to deflect it back at Terra-Xehanort, your safest bet is to get as far as possible from the supposed point of impact