Episode 29

Act of Treachery is the fourth episode of Ao no Exorcist's second season anime.

Synopsis
Ryuji tails Juzo to the Deep Keep, finding several Exorcists incapacitated in his trail.

Rin finally lights two candles properly, but Shura reminds him this is only the starting line. He remembers the fate he was bestowed by Mephisto's wager on turning him into a weapon against Satan.

Juzo confronts Mamushi in the Deep Keep. She tells Juzo it was to open Myoda's eyes, recalling when Todo informed her of the Left Eye being held in the Deep Keep as Mephisto's personal property, while a Right Eye also exists. She wants to expose Mephisto, Tatsuma and the Japanese Branch for this. She says her basis of suspicion is from the hearing at the Vatican when it was outed Mephisto let a spawn of Satan live. She believes aligning with Todo will benefit Myoda.

Tatsuma, Yaozo and Uwabami are listening in from a security room. Juzo and Mamushi charge at one another, Ryuji jumps from the shadows trying to stop them. Tremors spread throughout the area, Shura and Rin follow the source to investigate. Tastuma says there is an intruder in the Deep Keep. The ceiling of the Keep rots through, Todo descending before Juzo. Juzo swears Mamushi is being tricked by Todo, despite her and Todo denying it. Mamushi says everyone else are the ones being deceived before removing the Eye from it's confines and using it to disappear with Todo.

Ryuji confronts his father about Mamushi's claims, Tatsuma avoids answering by saying what is happening is a secret that he cannot tell anyone, not even his own son. Rin witnesses Ryuji disown his father in front of everyone. Tatsuma dismisses his son's concerns as though he is a child that doesn't know vital information. Rin remembers the last time he spoke to his Dad, how it ended with him having regrets. Rin doesn't want Ryuji to carry the same guilt.

Emotion causes Rin's flames become visible as he begs Ryuji to not make the same mistake he did. Juzo knocks Rin away, recognizing the blue flames. Shura uses her abilities to bring Rin to his knees to control him, becoming more violent with his punishment as he disrespects her in front of everyone. Yaozo demands an explanation from Shura later.