Agron (SaGa)

Agron is a villain from Final Fantasy Legend III who guarded the Barrier Machine in Eastern Ruins which prevented people from accessing Xagor's territory (known as Goht) and could only be defeated by the use of Mystic Swords. The heroes of the story confronted Agron in battle after fighting their way to Eastern Ruins, attempting to slay him with the Mystic Swords but he informs them the Machine also protects him immunity to the swords and becomes temporarily invulnerable. However Agron didn't count on Dion, who had been installed with a bomb should such an occurance arise (we'll try not to question the logic, it is fantasy after all..): at any rate due to Dion's apparent heroic sacrifice Agron's machine is destroyed and the monster's immunity to harm was shattered. Agron was understandably rather angered at this and attacked the remaining heroes, calling them "puny humans" before attempting to kill them, only to meet defeat himself during the battle.