Technically. Kokonoe didn't "brought her back"
Rather what Kokonoe did is
I believe what Kokonoe means by taking the matter in her own hands is that she finally have Celica with her. BTW her healing magic that can detonates Kushinada no Kusabi and Archenemy no.8 Rettenjou is not the same as Power of Order, but a different form of Anti-Body.
But either way, now that Celica is here, both Hazama and Relius is going to regret that they didn't kill Bang when they could have.