The Assistant Archbishop, he oversees the teaching of acolytes (people who will take the exam to become a priest). He was Frau's teacher in the past, and is his most important person. (Wiki)

Barsburg Empire's Military Academy is known for training elites who bring victory to the empire. Students of the academy freely utilize an ability called "Zaiphon" to fight, while the types of Zaiphon usable depends on the nature of the soldier. 
Teito Klein, a student at the academy, is one of the most promising soldiers produced. Although ridiculed by everyone for being a sklave (German for slave) with no memories of his past, he is befriended by a fellow student called Mikage. While preparing for the final exam, Teito uncovers a dark secret related to his past. When an attempt to assassinate Ayanami, a high-ranking official who killed his father, fails, Teito is locked away awaiting punishment. 
Only wanting the best for Teito, Mikage helps him escape. Teito ends up at the 7th District Church where he is taken in by the bishops. It is here that Teito attempts to evade the grasp of Ayanami and the Military, so he can rediscover his memories and learn why he is the person that can change the fate of the world. 
[Written by MAL Rewrite]

Barsburg Empire's Military Academy has always been known for training the elite with potential to become superb soldiers who won't bring shame to the name of the empire. The students of the special program freely utilize an ability called "zaiphon" to fight... Everyone's capabilities are different, and in many cases, reflect their nature. 
However, not everything is what it seems, and nothing will be the same for Teito Klein after passing the last exam... 
(Source: Timcanpi)

Bastien