Well, if you already have carpal tunnel, you probably should either get some ice ready or just skip it because it's fucking garbage and I'm not exaggerating, I had to take breaks. As in pause the game and stop in the middle of the fight to let my hand rest because it was so tired from spamming the square button. I hated it.
Like, I have a very
weird relationship with BBS. I love that game so much, but it's optional bosses are so fucking ass and I have no idea why I even tried to beat them on the PS4. I mean, I did it, and I guess that's just the completionist in me but it's as bad as Bizkit says. Maybe worst.
The Unknown is best beaten as Aqua, however Ventus can manage the challenge..
But Terra is basically the 9th Circle of Hell in terms of fighting this guy.
You will need to dodge roll
non-stop through the
entirety of the fighting. Literally. That's not an exaggeration or statement meaning "dodging a lot." You will need to
continuously, non-stop, every moment of the fight when you're not attacking, being performing dodges. Because the attacks the Unknown performs are unpredictable, and
unblockable. There is no safety and no way of being able to react in time for most of his attacks, meaning
you have to rely on invincibility frames to survive. There's absolutely zero pattern save for certain attacks of his becoming available and/or
combining as his HP goes down. He can literally do anything. No fight is ever the same because it's seemingly shuffled each fight. Some fights he may be chill and do his slowest most easily telegraphed attacks. Others, he may just come at you like you killed his cat. It just depends on his mood
...And then he becomes
invisible. Just straight up invisible. No way of seeing where he is on the map unless you see the attacks he performs. So you're just attacking in the general direction of where you
think he is with Surge type of attacks in
hopes of connecting and ending the fight.
Oh, and if you combo him with too many hits, he'll either put up a shield that turns the hits you deal him into HP recovery
or he'll straight up rewind time to exit the combo, undo the damage and then counter you hard. This is why you cannot rely on actually attacking him. You just have to spam Thunder Surge. It's the only attack that deals a great amount of damage, does not initiate a counter, and leaves you invincible as you attack and gives you safety to dodge after you do it.
I'm serious, it's a garbage ass fight and completely the worst optional boss in Kingdom Hearts history. I hate it and will never fight it again.