@ez3 That kid is probably a trap. Seeing as they have 0 mana, there's no way they'd get the idea to become a disciple of a demon lord. Meaning someone sent them in to try to get into Zagen's bubble. Either to spy, or do harm.
@Kaarme@Anzera@KazutoKatsuragi@Lolipop_Candy
Even if the extremely suspicious coincidence of the box were not enough (he JUST talked about the same episode, what were the chances?), not being a cute girl is an immediate red flag...
Well, since there are so many speculations already, I'll tell you this. Be wary though, each new line is an even further spoiler.
1. Yes, that Nero kid is Bifrons, the same archdemon/demon lord that invited Zagan to the party.
2. That choco Nephie? She's Bifrons' disciple.
3. Of course this won't be the last arc Bifrons appears.
An even further spoiler, only for you the brave ones:
4. Choco Nephie is actually less of Bifrons' disciple and more of a test subject/slave. She despises Bifrons with all her fiber being. Guess what kind of fate will wait her.
Calling it now: Nero is Bifrons. I was just rereading the earlier chapters, and in 9 when Zagan meets the other demon lords we can briefly see one face. It's definitely Nero.