When Martin sacrificed himself to Akatosh in order to save nirn did Akatosh permanently get his body as a avatar or was it a one time thing?

and I know malacath is a daedric prince or what was left of him but there was a bit of information what I read what said trinimac was

imprisoned in the deepest part of oblivion is this true

Trinimac is Malacath.

Three daedric princes; Boethiah, Azura, and Mephala, convinced a sect of Aldmer to follow a different path (they are today the Dunmer, or the Dark Elves). Trinimac, champion of Auri-El (the aldmeri aspect of Akatosh) attempted to intervene. In response,Boethiah ate Trinimac, used Trinny's voice to give lie to the Aedra's way, and then pooped (yes, pooped) Trinimac back out as a final insult. Trinimac was corrupted into Malacath, and his disciples were corrupted by proxy. His disciples today are the Orsimer, or the Orcs., the Pariah Folk. It's the point when many lore buffs consider the Aldmer to have stopped being "right" since they shunned the Orcs.

That's why "Dung heap" or other slang terms for fecal accumulations can be considered an insulting epithet to orcs.

Malacath himself has told us that the story can't be taken literally though . Trinimac is one of the least understood deities in TES, Rivaling Tall Papa in general obscurity. We know he was corrupted to become Malacath, and that Boethia helped it allows my, but we don't really know the specifics of the transformation.

I've always interpreted the supposed imprisonment in Oblivion as a sort of self imposed exile after the murder/execution of Lorkhan. Trinimacs role and expression changed with that act, and Boethia was simply the last nail in the coffin, so to speak...

As for Tue Martin-Akatosh thing... When Martin mantels Akatosh, he literally became the Dragon of Time. Akatosh gains nothing, really, as it's just two beings becomming one.