Corin Charite is a reincarnated Judas Iscariot.
All of the other characters have some relevance to the Christianity theme; then we have Corin, who represents "energy conservation". No, this is just the cover. Lucifer/Mikaboshi has been quietly shuffling people out of Hell (once they've served their time) via reincarnation using her Shinto Mikaboshi portfolio and has been hiding this from Heaven. Judas's sin required some kind of karmic response; being reborn as a vampire would cover that, but Mumumu made certain it was into a Vegetarian Vampire, so Judas' soul would have a path out.- Mumumu has been avoiding Iesua so well that she doesn't realize that Iesua just wants to forgive her and Judas; she thinks Iesua is going to permanently damn them all.
It is impossible for Iesua to get drunk.
Wine is symbolic of Christ's blood. As such, Iesua already has a lot of natural alcohol in her body.