I have just watched the 49th episode of Dragon Ball Chou.
Trunks returns from the future in order to seek help for defeating Goku Black. During his speech, he explains how he prevented revival of Majin Buu by killing Dabura and Babidi.
How could this be possible? Haven't Dabura and Babidi been killed in the current time line? How can someone who is killed exist in the future? Can you explain the logic here?
The future timeline already diverged from the main timeline when Trunks saved Goku. Think multiverse theory. Nothing that happens in the past has affected the future. That's the reason Cell existed in the future, even though he was killed in the past. It's also why all the characters remained dead, even though they were alive in the main timeline.
That considered, the future timeline had its own unique past, where Babidi and Dabura weren't killed until they encountered Trunks.
