Game: FF8
Summon name: Infinity Knight
Attack name: Sword of the light
Details: The Knight will drop from the heavens, with his sword. He will then fly forward and strike the enemy, leaving the slash mark in him in light, which will then pour out light and envelope the enemy, doing massive damage.
Damage: This summon unboosted at level 99 is just slightly weaker than Eden fully boosted at level 99. Has a short summon tme, but a fair amount of time for boost, about 10-15 more than Quezacotl.
Acquired: After you defeat the Omega Weapon, you will be able to exit out into the garden of the castle and go through a maze, with many new enemies stronger than omega weapon(I had to give this summon a reason

). Near the end of the maze, you will find this Gf. You must fight it and win. The battle isnt quite as hard as Omega Weapon.