Here's an idea that just occurred to me.
Trinimac/Malacath(I'm not 100% they are the same entity) is an Aedra if not mistaken? And the only Aedroth that you can talk to and that has a definite sense of power. You can't call him a Daedroth because, by definition, he took part in creation?
So here's my idea, what if Boethiah didn't "eat" Trinimac in the traditional sense but more over rescued him? In Boethiahs stomach, granted some power and the stress of this changed Trinimac into Malacath? Boethiah gave Trinimac power to survive creation where the others didn't. Afterwards Boethiah was granted the Goldbrand. Even Malacath is quoted to saying "you are too literal minded" when asked about it.
Thoughts?