Ruri is Kosaki's ride-or-die best friend and one of the select few who knew about Kosaki's crush on Raku early on. She's basically appointed herself as Kosaki's emotional support system, constantly pushing her to actually do something about her feelings instead of just silently pining. Fans often note that Ruri's willingness to give Kosaki that extra nudge—sometimes literally—is what moves their relationship forward, even when Kosaki's too nervous to take the leap herself.
Content compiled by AnimeList.moe from publicly available sources.
