Operation Mi'ihen (Final Fantasy X)

Operation Mi'ihen was a violent attempt by the Al Bhed and The Crusaders to use forbidden Al Bhed machina weapons to destroy Sin. The attempt ultimately backfired when the Sinspawn they gathered to lure Sin fused together into Sinspawn Gui and then proved fatal when Sin appeared and destroyed the machina and decimated most of the Crusader fleet. Among the commanding officers in the battle was Chocobo Knight Lucil, who managed to survive the attack with comrades Elma, Clasko, and a single chocobo.

Aftermath
All of the Crusaders were excommunicated from Yevon, who had condemned their actions prior to the failed attempt. Many of the Crusaders retired, while others went to work for temples of Yevon, including the nearby Djose Temple, to seek forgiveness. Many of its other surviors, believed to be dead, were found by LeBlanc and became members of her syndicate.

Likenesses
It is interesting to note that the idea behind Operation Mi'ihen, that the separated parts of Sin wish to be rejoined with the creature itself, is strikingly similar to the idea behind the Jenova Reunion Theory in Final Fantasy VII.