Isaac and the Black Sword Knights are responsible for training the Maihama army. While he's in Maihama Isaac gets to know the new crown prince of Maihama, a young boy named Iselus.  Iselus respect looks up to Isaac and respects him.
At a party for the crown prince's birthday, assassin's make an attempt on his life.
Well, it's our job to protect him, Isaac.
Prinz Itherus zu beschützen, gehört auch
zu unseren Pflichten, Bruder Isaac.
Bueno, nuestro trabajo 
es protegerlo, Isaac-kun.
Protéger Icelus fait aussi partie
de notre devoir, mon petit Isaac.
Beh, è nostro compito proteggerlo, Isaaccuccio.
Bem, é nossa função protegê-lo, Isaac-kun.
Ладно тебе. Защищать господина Исельса
тоже наш долг, дорогой Айзек.