This is Prob one of the best reaction I’ve seen since you used something nobody uses and ur edit is great just ya know hope ya get better in the future!
I have an idea, you could do Alto as the Doomslayer, where he's like that because the demons attacked and killed his friends, but leaving vermail unconscious, which made alto angry, so he killed the demons, and he found the source of the attack leading to a portal to hell, he went in to destroy the portal from the inside and decided to remain in hell to fend off the demons, and at some point he was sent to Argent D'Nur. After that just continue the story with the basic doom lore following his arrival to Argent D'Nur and the events of doom 2016 and Doom eternal with some modifications, like vermeil always being with him when she woke up after her and alto's friends were attacked, and from there you could make your own modifications, also doom 2 and doom 64 dont happen in this timeline, so yeah, tell me if you think it's good😁