Ao no Exorcist episode 19

It aired on Sunday, 21 August 2011.

An Ordinary Day

The Exwires learn that Kamiki's birthday is coming and they decide to make a surprise party to her. Despite all their efforts to make the party a secret, Kamiki ends up figuring the truth and claims that it should also be dedicated to those whose birthday already passed too. In the end, the party becomes a celebration to everyone's friendship.