I agree with this theory, it seems that from the beginning before this incident happened Ml was already in love with MC, and Ml was the trigger that if he died the tragedy would happen all over again.
Because only Ml himself has scars and remembers all the plots, and ML once said that if MC dies we will start over again.
As if he wanted to convey that if MC dies I will also die either by suicide or something because he loves MC. Why would he live if The person he loved died
THIS!!! notice how the other people who was predicted to die didn't have any scars on them after the loops? And then mc who was seen to die multiple times also doesn't have the scar, So how come the dude has multiple of them? The last time they saw him he didn't have any scars but when he seemed crazy he already had them. He's the reason and MC is the trigger, He dies after mc died (suicide) because of how he would follow him after death and find him when they go through a loop again.
It's probably a loop or MC and the dude regressed back whenever MC dies(dude just follows) and that's why dude knows a lot about mc and since it foreshadowed not only one scene from their past but multiple cause some memories doesn't aline with each other, Dude's death probably has something to do with scars like if he died by getting his neck chopped off then that's why he has that kind of scar rn because in one memory he had a scar on his neck the other he doesn't and in another he has the scar on his neck and I think some on his arms as well?(don't quite remember couldn't keep track) As for MC not having any scars, I haven't gotten to that conclusion tbh. It's probably that he's the trigger or they're both the trigger or not the dude is the trigger of them going back in time, In my opinion it's the dude who is the trigger and not the mc. If mc died before dude then why does it seem like they only regressed after the dude dies? And it's only the dude that remembers all their memories and has the scars from his death in the previous lives.. so In my perspective mc isn't the trigger and the dude is the trigger, he's just kind of the trigger.