Council of Swordmasters

The Council of Swordmasters (剣聖会, Kensei-kai) is a group of the most renowned master swordsmen that assembles in times of crisis. According to Haragiri, the council was created to improve the swordsmanship of its members.

Monster Association Arc
The members of the council were called by Atomic Samurai in effort to convince them to help defeat the "Hero Hunter" Garou. The motive behind the meeting being that Atomic Samurai worries that, despite Bang's strength, he might not be able to bring himself to kill his own student, thus Atomic Samurai wants to find Garou before Bang and kill him. The council agrees to Atomic Samurai's plea for which he is grateful, but Haragiri reviles his plea and status as a hero. Haragiri shows the Monster Cells he has received from the Monster Association. He tells them he had already ingested one and transforms into a Mysterious Being. As he orders the others to eat the cells and attacks Atomic Samurai, Atomic chops him into pieces with his Atomic Slash.

Trivia

 * They are also known as the Holy Order of the Sword in the subbed version of the anime.