Ruined Fate is Aiden's Wild Card for any wild situation like this. Its name is Ruined Fate because it reverses what Fate had in store for any person or thing. For example, if someone is destined to become extremely strong in the future, it reverses that fate and makes them extremely weak.
In the case of the Ancestor, he was supposed to die due to exhaustion of his lifespan. Instead, Ruined Fate rejuvenated him, making him younger by many years and reversing his exhausted lifespan into one with an abundance of life.
"Hahahaha, I don't know what you did, but it seems whatever you were trying to do backfired," the Ancestor laughed as he smirked, releasing his martial spirit. His realm is now Middle Spirit God. "Thanks to you, I am now a Middle-Level Spirit God," he said, clenching his fist and enjoying the power coursing through him.
