S12·E27 The 13th Rider

A young boy learns about the Rider War and steals Shinji's Deck before coming to realize that it is not all it is cracked up to be. Yui, after a confrontation with Shiro in the Kanzaki Household learns that her brother is dead The 4 remaining Riders meet a new Rider, claiming himself to be the "13th" Rider.