KH2FM+ CM - Barbossa
Disclaimer: Kingdom Hearts 2 Final Mix + belongs to Square Enix and Disney.
Some find this easy, some find it hard. Depends on how you fight it.
If Jack dies, you WILL lose.
Thunder stuns him, I am not sure why it stopped working after the first few times.
Whack the heartless to death, cast Thunder on Barbossa, hack away, and get back before he recovers. Repeat, you can also throw in Jack's Limit if your low on MP.
Eventually, he will call the heartless again, and it will dash around this time. Since I used Wisdom Form + Thunder he did not show much, but he has some annoying attacks, mainly his gun.