A Slime Dance From the Reze Dance Choreographer
The video is short, bouncy, and built around one move. Rimuru opens by forming a hoop overhead with both arms, a bit the collab is calling the "slime dance," then keeps going through a pop routine set to "Rapappa☆PARTNER!" Japanese anime news site Anime! Anime! reports that the track is from Okasaki's third mini album MY ÉTOILE, which came out September 2, 2026.
The choreography credit is the detail that matters here. Bunkei (ぶんけい) is the choreographer behind the "Poke Dance" and the "Reze Dance," two routines that spread far beyond their home franchises. Anime! Anime! describes the result as a pop routine that's fun to watch even if you never try it yourself.
The song itself has anime-industry names behind it too. Lyrics are by Miho Karasawa, who also records anime theme songs under the name TRUE, and composition and arrangement are by Yuki Honda of EverNest.
This is a manga-side collaboration rather than an anime one. The dancing Rimuru comes from the comic version of That Time I Got Reincarnated as a Slime, drawn by Taiki Kawakami and published by Kodansha in Monthly Shonen Sirius. The video was posted through the magazine's X and TikTok accounts, with a side-by-side version of Okasaki dancing next to Rimuru on her own official accounts.
Fans React: "Is This a God?"
Japanese X users were not subtle about it. Reactions collected in the Anime! Anime! piece include "too perfect," "so cute I watched it over and over," "what is this, a god?!" and "a Demon Lord has no business being this cute." Several comments imagined Rimuru's own subordinates losing it, with one predicting Shion and Diablo would pass out from nosebleeds and another saying Diablo might casually die from the cuteness. More than a few said they want to memorize the routine and dance it themselves.
Okasaki's Very Busy Year
The collab lands in the middle of a big stretch for Okasaki. She's currently leading Season 4 of That Time I Got Reincarnated as a Slime as Rimuru, and she voices Hinana Ichikawa in THE iDOLM@STER Shiny Colors, which played K-Arena Yokohama in April. Last year she took home the Best Lead Voice Actor award at the 19th Seiyu Awards.
September is her anniversary month as a solo artist. The album came out September 2, and on September 13, 2026 she plays a fifth-anniversary concert, "5th ANNIVERSARY LIVE Floria" (フローリア), at LINE CUBE SHIBUYA in Tokyo. The matinee and evening shows carry different subtitles, "My Heartbeat" (僕の鼓動) and "The Sound of a Promise" (約束の音), and each is planned around its own theme. General tickets are on sale, along with a discounted "celebration" ticket (かけつけお祝いチケット).
Where Tensura Stands Right Now
That Time I Got Reincarnated as a Slime, known to fans as "Tensura," started as Fuse's web novel on the Japanese fiction site Shosetsuka ni Naro. The premise is right there in the title: an ordinary man is reincarnated in another world as a slime, then uses the skills he picks up, along with wits and nerve, to build a nation of monster allies.
The anime, produced by studio Eight Bit, began in October 2018. It has since expanded into the theatrical film Scarlet Bond (November 2022), the three-episode streaming special Coleus' Dream (November 2023, part of the web novel's 10th-anniversary project), and a second film, Tears of the Blue Sea (蒼海の涙編), which opened in Japan in February 2026. Season 4 started airing in April 2026 and is planned as a split five-cour run, which is a lot of slime.
Looking Ahead
Okasaki's anniversary concert at LINE CUBE SHIBUYA is today, September 13, 2026. The next dated milestone on the manga side is volume 33 of Kawakami's adaptation, out in Japan on October 8, 2026, with a special edition bundling a mini clear file out the same day.
Internationally, Season 4 streams on Crunchyroll as it airs in Japan. The manga is published in English by Kodansha USA, which shipped volume 32 on June 9, 2026, so English readers are close to caught up with Japan. No word yet on whether the dance video itself will get an official international release, but it's already circulating on the Monthly Shonen Sirius X and TikTok accounts, which aren't region-locked.
(C) Fuse, Taiki Kawakami / Kodansha