This goes infinite with phyrexian altar and enough demons in the 'yard. At least until you strip every demon out of your own deck, then win? I didn't even notice the All graveyards on the 2nd trigger, so when going for the loop you can even use your opponents demons to your advantage. Sac all the demons one at a time, then sac him, Recast, ETB Trigger brings em all back, get all the demon ETBs, then sac again. Resistant to removal too.

There aren't really a lot of demon tribal decks running around and I can only think of like maybe three demons that see play otherwise on a common base (that being Blood-Gift Demon, Rune-Scar Demon and maybe Razaketh), so the second ability triggering for every 'yard don't really matters too much I think.
Also while there are some strong ETBs among demons, neither of them wins you the game on the spot, as either Rune-Scar Demon or either of those demons with a boardwipe upon ETB are probably the strongest of the bunch. More game winning would probably be a Blood-Artist like effect, but you don't actually go infinite as at a point your commander would cost more than you have demons to sac.
Don't get me wrong I totally agree that it is powerfull, tho if you want to go the aristocrat way, there are probably more reliable options for you as it is an archetype overly exploited already. Still, might be something to think about and maybe limit the reanimation to like 7 at once or something, given it fits into the text-box as I'm running out of space x3
Either way, thank you for your feedback^^

Hmm. I doubt we'll see a lot of Eminence in the future because the mechanic resulted in commanders that some consider to be a little too powerful (since you don't even need to cast them to gain their benefits).

In this case, I think the Eminence trigger on it's own is fine. However, I feel like both the indestructibility and the stat line, when you factor in that this will resurrect all the demons in the yard (which should have accumulated thanks to Eminence) this card might either a weaker body or some other form of down tuning.

Also, his name is "Arthaalon", but the text on the effects reads "Bazorn"

I know Eminence is pretty powerfull, tho I think there are ways to balance it and not all Eminence commanders are that powerful either, just look at Arabho, he was pretty meh.
In general I actually think only Edgar Markov was overpowered. Ur-dragon and Inalla are strong, but I think still reasonable. Tho I might be off with Inalla, as she got utterly overshadowed by Kess, I didn't see her that often to actually be sure. But of course, that's just my thoughts on that. I also went with Eminence here because it fit the flavor of the demon god.

Also, thanks for pointing that out, I fixed the names in the abilities now and by that I took the keywords out as I otherwise would have run out of space. I guess that's one way to fix stuff lol. I miss the trample but never have been happy about the indestructible, I just had no space to put another 'God-Rule' in there.