"Knight of the Secret Stone! Fusion User "Masumi Kotsu" is the tenth episode of the Yu-Gi-Oh! ARC-V anime. It first aired in Japan on June 15, 2014.

The second match is a Duel between Yuzu Hiragi and Masumi Kotsu from the LDS' "Fusion Course". However, Yuzu has doubts over whether or not Yuya might have been behind the attack on Sawatari or not, which causes her to hesitate and misplay during the Duel. And then this battle between Duel Schools reaches its conclusion in the third and final Duel.