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.
Sword of Pain Black!
¡Sword of Pain Black!
Black Sword of Pain !
Sword of Pain Black!
Sword of Pain: Black!
Клинок Чёрной Боли!