A thief has stolen the Left Eye of the Impure King, a piece of a powerful demon that had been safely sealed away. Yukio and Shura are sent to investigate while Rin accompanies them due to not being able to leave Shura’s supervision.
A continuation of the 2011 Ao no Exorcist series that acts as though the Anime original content of episodes 18-25 never happened. Unlike there, here the protagonist is treated with suspicion and fear because of his powers. Note that the series’ 13th and 14th episodes are mostly self-contained stories and were released separately in OVA format.
More Information:
aniDB (1, 2)
Crunchyroll
Fansub.co
Wikipedia