Terabyte672 | Final Fantasy VI Advance: Boss 20 - Ultima Weapon @Terabyte672 | Uploaded July 2008 | Updated October 2024, 12 hours ago.
I'm messing around with screen settings, so hopefully this video will have pretty good quality. If it does, I'll use the same format to record the others.

Use your best magic against Ultima Weapon, as his Magic defense is much lower than his weapon defense. He has some pretty nasty attacks, so don't be afraid to use Cure spells on your pary if you can.