S6E171 : Revenge

Yamamoto defeats Genkishi and incapacitates him. While Genkishi expresses his disappointment not being one of the Real Six Funeral Wraths and not being appointed Byakuran's most trusted soldiers, Kikyo uses his box weapon and kills Genkishi. Kikyo reveals to Genkishi that it was under Byakuran's order to kill him when his usefulness is fulfilled. Tsuna's friends realizing, Byakuran's true nature, become even more motivated to win the battle of Choice.