Asiel regressed because he touched the remnants of the dark magic ML casted to return back time.
Now this part is just sad cause he retained his memories. He saw ML’s rampage when FL died and saw him kill the aide.
When his parents disappeared he was like where is everyone? Where’s mom? Why did dad hurt Ruth. I wanna see mom.
So when he regressed, he went back to the womb. When he heard the FL’s voice he calmed down. From there he just waited until he’s born.

1st Life
ML thought that the wife is protecting the empress and feigning memory loss. Still like her tho but NOOOO she’s the “daughter of my mother’s killer” type shit so he denies his feelings. Treats her coldy but secretly horny for her. One drunken night boom pregnant oh nooo still daughter of the killer so imma head out and find evidence.
Found out some clues about it but still can’t prove shit. Also found out that there’s a curse on the FL, it’s connected to mana. If he used too much mana the FL’s life will be drained so he’s now looking for a way to remove that. He met Miela the priestess and she was kinda ohhhh use meeeeee. Cause one requirement of the curse is that the FL and ML should love each other. The FL loves him and the ML loves her so the curse got there. Anyway, Miela was like, if she gets jealous enough or got like pushed away enough she might not love the ML anymore thus she won’t be cursed anymore. ML is like “killed too many black magician so I’m kinda numb but not THAT numb that I’ll sleep with you but I can do the minimum amount of flirting for gossip” type at the time so he kinda agreed with Miela’s plan. So he brought her home. The part where the FL saw them, Miela is healing the ML or something. ML was thinking ugh the FL still loves me (cause she’s still cursed) what more should I do so she hates meeeee. I don wanna see her cursed anymore. I’m tired bruh, I killed sooo many black magicians (cause if he killed the right guy the curse might disappear but he’s not lucky with the RNG) it made me numb what more should I doooo. While he’s thinking that Miela was flirting with him. She came onto the ML and said sleep with me, we’re already like a “thing” so why not do it. Like really, I’m kinda desperate here. You want her to not love you anymore right? With great timing the FL saw them, this is when Miela jumped into his arms. ML was gonna push her away but saw FL and got convinced with what Miela said so he reluctantly hugged her.
Fast forward, FL died, ML was away at that time looking for a way to remove the curse. Then he had the realization. I don’t wanna be a jerk anymore. I’m gonna be a standup guy and love my wife and kid, be honest about the curse with my wife and be there for his family. BUT HAHA JOKES ON YOU SHE DEAD.
ML went into super saiyan mode and killed everyone, almost killed the kid but stopped himself and remembered he was researching time reversal spells cause his parents died. He tried the reversal spell and put his wife as the main regressor so she remembers that he’s a jerk and she stay away from him. When they disappeared Asiel was left alone. In the crib and saw his parents disappeared. He climbed out of the crib and stepped onto Ruth’s (ML’s Aid) blood and went over to the remnants of his dark magic. He got regressed too. Poor boy
It’s too long so I’ll end it here LOL that’s mostly what happened in their previous life.