User blog comment:B214/Volume 22 spoilers/@comment-9595671-20160814045836/@comment-9595671-20160814051328

That's what I think, mostly because I haven't seen anything about the status of the Magician faction so it seems like they were still able to act if needed.

In fact it seems like Rizevim was too focused on the members of Qlippoth that he forgot about them. Though with what Apophis and Azi Dahaka said to him before he died about his poor planning... that could probably explain it ^^;

So it seems like that faction is still strong enough that the remanents of the Hero and Old Satan factions could team up for a last attack.

Wonder if they'd do it through Indra, I do recall Indra saying if he felt Issei became too big of a threat he'd take care of gim and his DxD form may have finally pushed him far enough for that.