Gigamesh
Non = Elemental
Gigamesh returns from a previous FF as a replacement for Odin. He appears randomly even in boss fights and attacks by choosing one of four swords. Each sword gives him a separate attack. The four swords are; Zantetsuken - Cuts all enemies in half resulting in death. Masamune - Extremely strong attack against all enemies. Excaliber - Strong attack against all enemies. Excalipoor - 1 damage to each enemy.
If you have Odin before you face Seifer on Disk 3 then Odin will appear. Seifer will reverse Odins' Zanzekutsen killing Odin and Gilgamesh will replace him as your random guardian.