Voice of Reisen Udongein Inaba in Cookie☆☆ S3 and Kaenbyou Rin in Nabe☆. As Reisen, she has swept bangs and a single bent ear, often breathing fire from a random one-shot joke in 2015. She is still active as a virtual youtuber.
She was initially the least popular character of Cookie☆☆ S3, with almost no fan art or MADs. However in 2016, a single user by the name of Ants began posting MAD ranking videos as if she was a popular character like Majime-kun. Other users began ironically making MADs starring Hisui, which would then get added into Ants's rankings, which would then cause more people to watch them. This began the "Unprecedented HSI姉貴 Boom" where derivative characters with almost no connection to anything Hisui herself ever did were made.
This rapid escalation also caused a number of running jokes. One that carried over from Reisen is fake or detachable ears, except that Hisui's aren't and ends with her comedically spewing blood everywhere. Another is Reisen's affinity for guns, except Hisui prefers shotguns alongside Rurima. Her voice remixes include chirumiru and shin takarajima.
Parody derivative characters include: