Depends which bible you adhere to.
Comics he is a god of chaos, as he is in armada-cybertron ( I reference cybertron for his new tank ship mode). As long as Yin, or hate exists, he will exist. As he's part of the natural order of opposites. Yin to primus' yang. Destruction to creation, death to life, or in simplest terms, black to white. He is the complete inversion to what primus is barring the cosmic aspects.
G1 toon, and Japanese story, he's a spark who won't die, but his initial body was organic made. Primacron built him with his assistant the oracle who later becomes vector sigma and the matrix.
Welcome to the continuity nightmare, pick your poison.
Now as a god, he can be omniversal, omniscient, and omnipresent, BUT that doesn't mean each body was created in the same manner. Just because he's omniversal doesn't mean his origin is the same in each timeline, just that each timeline has a body for his spark to inhabit. Ditto to primus.
Omnipresent = he exists in all timeframes of said timeline (or at least his spark does)
Omniversal = he exists in all timelines
Omniscient = he sees all
These issues could really only be solved by an omnipresent spark, that even in being destroyed in the original movie carried on just fine without his body, but needing a new form to inhabit in that universe to do anything other than minor things like rebuilding starscream.
So basicly he has a form for every universe, whether it's a ship, planetformer, or cube, he still has a place for his power/spark to spill over into for said universe when he pays his visit. Until then, various things must make his notice for his form in said universe to 'awaken'.
G1 is moot as it basicly is what the rest splintered off of so to speak. This also explains his 'hibernations' in various universes. Including his stasis in armada as a smaller moon.
So essentially, even in
G1 toonverse, even though Primacron built him. Unicrons Omniversal spark gave it power. Now unless they create some bit of fiction that explains both primus and unicron were assistants to primacron, who's sparks gained in power over the eons to become cosmic beings. That's about the only way to sum it up, yin and yang, just various origins for said universes to become receivers of said power.
Essentially he's a universal truth, like primus. Creation vs Destruction, hate vs. love, if you destroy one, you destroy the other, or cause a complete and utter universe nullifying mess... Or blackhole. You can't have one, without the other. Even in movie-verse, I expect some form of opposite to the allspark, the creator of life on that cybertron. Movie-verse for now, kinda sidesteps the issue by having the allspark be a TMA like construct. (2001: a space odyssey movie/book, and the subsequent books. Though even Unicron can be written in much the same still.)