the Manberg VS Pogtopia war is just Wilbur being salty that Shlatt won the school elections, and that he and Tommy got moved to another class

the Disc War is because Dream stole 2 of Tommy's Physical Copies of his two favorite games

the Pet wars were because Sapnap "hacked" everyone's neopet's accounts or some shit (they were too dumb to give him the password themselves)

Techno was in uni and came back to Wilbur and Tommy chanting "ITS THE BLADE" and forcing him to help them bully kids

Wilbur dying is just him being suspended and having Philza pick him up from school, Ghostbur is a transfer student that got accused of helping Tommy do something to dream (idk yet), and got suspended too

SPEAKING OF PHILZA, the only things he knows about this whole school drama is things his kids randomly talk about on the dinner table

Karl "time traveling" is just him waiting outside other schools and asking anyone he sees for help with his history projects

"Tommy got beat up in detention today"

"Wilbur, I don't think it's a good idea to set off fireworks in the schoolyard"

"Foolish, would you help me and Ranboo build a treehouse if we give you 20 bucks?"

"ERET HOW COULD YOU PROMOTE DREAM'S CAMPAIGN?! WE TRUSTED YOU"

"Mr. Sam let me in the detention room, Mr. Sam please I left my journal in there, Mr. Sam please"

"Ant and I are inviting you guys to our party, we promise not to throw eggs at you this time"