Ruri was briefly mentioned during Yuto's flashback. After the latter's encounter against Yugo ended, Shun Kurosaki asked Yugo about the whereabouts of Ruri. Yuto responded that he didn't know, prompting Shun to curse.
Although Shun initially paid no heed to Yuzu, once he noticed her, he mistook her for Ruri and asked if she had escaped with her own strength, much to Yuzu's confusion. Yuto insisted that Yuzu wasn't Ruri and knocked Shun unconscious before Yuzu's bracelet teleported them away.