So, he drinks the blood of his enemies from tea cups?
I would be pretty sure that's human (or possibly deer) blood. I forget where I got this impression, from some extra-canon source, but Alastor is one of the few demons who can permanently kill other demons, who ordinarily have some level of toon immunity from anything other than things like the Exorcists and those flaming twisters in Wrath (and perhaps really big falling rocks).
I just listened to the Moxxie/Millie song from the first half of the finale again and holy shit this is the cutest most adorable goddamn thing I've ever heard. The general concept, of a naive imp going to Ozzie's to sing an innocent love song, is good by itself, but Mox isn't actually that dumb. I think he knew how Asmodeus was going to react.
And I'll note that after Asmo threatened him and basically ordered him to sing something more perverted, he went right back into lovey-dovey shit. And then the audience actually applauded before Asmodeus threw him out.
Also just as a musical number it was pretty amazing, you had at least four people in it, Mox, Asmodeus, Fizzy, Verosika (with a truly vicious diss verse), handing off the melody to each other repeatedly.
And both Blitz and Stolas get called out and humiliated to the point I felt sorry for both of them.
I actually have some optimism for the future of, if not this show or the main show, the general future of Vivz. She knows how to evoke feels and thunks and there will always be a market for that.