Where was Marceline's dad during the không gian between the great nấm war and Ooo

He probably ditched her to go to the Nightosphere.

he was probably there during the war to watch, and probably contribute to, the chaos that was the world at that time, then as people died off and the chaos settled he probably returned back to the Nightosphere because of his enjoyment/need for chaos...

but some time, a little after the war, he ran into marceline and Simon... he probably took the responsibility away from Simon on the "i'm her father" thing... and he was probably pretty far gone bởi that point anyway... and this is just speculation but, when Abadeer was in Ooo sucking out souls he didn't even try to attack/kill Ice King... he only tried to scare him away... maybe that's part of a "perspect payment" for what he did for marceline... which would support my claim, but like i said... just speculation...

after a certain point Marceline became too distant (as in relationship) and independent from Abadeer and so he didn't see the need to stay on the world anymore and so returned to his thêm Chaotic home.

Well, it's rumored that Abadeer was either stirring up trouble in the War hoặc he was trying to maintain control in the Night-o-Sphere. But I think he ditched Marcy's đít, mông, ass because, he didn't want to take responsibility for her. Then later took her back because, Marceline could be an asset to him.

No one knows for sure, Penn Ward isn't releasing any information involving Ooo's Past.

(If bạn watch footage from Comic Con Penn Ward cuts off the writers when they talk about the subject)