Kagemune is the Lance Group captain for the Salamanders. He led a group on a mission, to attempt to steal money and items from Lyfa and Recon. They managed to kill Recon but Lyfa escaped and they met Kirito. Kirito killed the two of his team members and left him alive after realizing he can't beat him.

Spoiler

He helped Kirito on his lie about him being the ambassador of the Undine-Spriggan Union by lying to Eugene that Kirito had an Undine Ally when his teammates were killed by him.