Quote Originally Posted by Depressio
yeah, i beat adel... i just junctioned my characters' strength to... a lot... and then i beat her... now i'm in that castle thingy, trying to fight that optional boss who casts "grand spark" or some kind of powerful thunder attack.
The boss your fighting now benefits from a lot of strength and magic power. So you'll want to junction as much Thunder-Thundara-Thundaga as possible to your elemental defense. If you don't have elemental defense for all three characters, be willing to let a few die and not revive them. They'll just die again anyway. The preferable thing to do is use Zell and max him out with Thunder element defense and Armageddon Fist your way to victory. The second choice is Squall.