Heh. Incarceration would be preferable.
These modrons twist/warp/break humanoids, compressing them into shapes--caged with their own bones, which are coated in metals--to create new modrons. The agony of the process, while "unfortunate," is part of what destroys the mind, allowing them to be magically reprogrammed into beings of pure order and obedience.
Hiya!
Ok, and this is good I guess? Or bad? I'd put it more towards "bad" because I like the whole "evil" idea of everyone and everything having responsibility for it's own actions. This includes all gods. I also go by the general standards of it1e AD&D, where is was technically possible to kill Zeus, it was so far off the realm of likely as to make it virtually impossible. And besides...we can read stories about heroes slaying gods. Not every day, but they are there. It makes for a really epic ending to a group of PC's adventuring days that's for sure! Hell, one of my characters (with, iirc, 7 other PC's and Henchmen) killed Lolth in the Abyss at the end of Q1 waaaaay back in the day. She was a Demigod, sure, but she just about killed all of us. Most of us were in single-digit or teens for HP's when she finally fell. One of the most adrenaline pumping combats I've ever had. In fact, after that adventure...we all retired. It was a great 'ending' for those characters story. After that, for a good 12 to 15 years (real time, not game time), the Drow were more disorganized than usual and they pretty much all disappeared from harassing the surface world. When a group of PC's actions can have that drastic an effect on a campaign, that's pretty special if you ask me.
Anyway, I never liked the "gods never die" concept for my Fantasy games. When a god can die from mortals, it helps keep them in check a bit...at least in my mind.Of course, YMMV.
^_^
Paul L. Ming
So, going back to Primus, I'm sure he has an opposite number, bringer of chaos, tempter of Rogue modrons, perhaps named Unicron...
I don't mind gods being able to be killed by other gods, so even in 5e I'd allow greater gods to be killed by another greater god. As for mortals killing gods, it should be impossible without some sort of divine aid, either from another god, some power equal in power to a god, an artifact/relic, or a prophecy. I'm sure there are other reasons I would accept if I thought a bit more about it. My point is that gods are not the next encounter to be killed by a band of PCs that wander upon it. Allowing PCs to just go god hunting reduces them from gods, to just another Monster Manual type creature.
To go back to the original question:
What do you need Primus to be for it to do the things you need in your game? That will tell you what it is.
Not if it's AL. I want Primus to be AL legal deity, he's got the power for it.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.