S04E91: What You Believe In

With no escape routes available, and Mukuro Rokudo being in a weakened state, Mukuro explains to Chrome Dukuro that it is up to her to win the fight. Drawing power from both her trust in Mukuro and the Vongola Ring, Chrome's illusions become far more effective, to where even Glo can't tell whether or not they are real. The fight soon concludes in a victory for Chrome, and the future Ryohei is introduced at the very end of the episode.