Mushoku Tensei: Old Rudy's Counterattack

Future Rudeus turns all the failures and regrets of his life into a warning for the Rudeus in the main timeline, ultimately helping the latter achieve a happy ending. In the original, the old Rudeus is an incredibly powerful magician, but despite having that power, he has no way to take revenge on the Man-God. What if there were a worldline where he changed how he used time magic, but didn't end up transported to a time before everything happened? How would he act then? Would he give up on himself, or use time magic to grow stronger and take revenge on the Man-God with his own hands? This is the old Rudeus's own revenge story. Entirely hand-written, no AI. I'm writing this just for fun and don't charge for it. The revenge plot later on should have a bit of a power-fantasy feel. OMO.