Tensei Shitara Akari dake Slime datta ken (転生したらあかりだけスライムだった件 Tensei Shitara Akari dake Suraimu datta ken ) (lit. That Time Only Akari Got Reincarnated as a Slime), officially abbreviated as TenAka (転あか),  is an isekai spin-off manga of YuruYuri written by Naya Minadori and Namori, and illustrated by Naya Minadori. The manga began serialization on Nico Nico Seiga in February 22th 2021.  Its first volume is scheduled to be released on August 31st 2021, along with YuruYuri Volume 20.
The manga is based on Tensei Shitara Slime Datta Ken (abbreviated as TenSura) light novel series.
Although being technically a doujin, the manga is advertised as an official spin-off of the series by Comic Yuri Hime's YuruYuri Twitter account and Namori.  Each chapter is released on the fourth Monday of each month. 
The June 2020 issue of Ichijinsha's Comic Yuri Hime magazine announced that Namori's YuruYuri manga will have an isekai fantasy spinoff titled Tensei Shitara Akari dake Slime datta ken (That Time Only Akari Got Reincarnated as a Slime), based on That Time I Got Reincarnated as a Slime (shortened to TenSura) light novel series. Namori is credited for the original work, while Naya Minadori is drawing the manga. The manga will run in Kodansha's Suiyōbi no Sirius (Wednesday Sirius) section on the Nico Nico Seiga website, but the announcement did not reveal the debut date for the manga. The release date was later revealed in February 2021 by Naya Minadori on Twitter, a few days before the release.
After an accident with a VR game, the Amusement Club members are teleported to a fantasy world with MMORPG elements. After regaining consciousness, Akari Akaza discovers that she has been reincarnated as a Slime.
It is also implied that TenAka is a crossover with Irusu no Yūsha Alicia, another isekai web manga also written and illustrated by Naya Minadori, released two months after TenAka. Multiple factors hint towards a relation between both mangas, like sharing the same slime enemies and the same fictional writing system.
List of chapters
|Chapter 1||Chapter 2||Chapter 3||Chapter 4|
|Related Manga||YuriYuri/Elegy Syndrome (2008–2010) • YuriYuri 2 (2019) • Irusu no Yūsha Alicia (2021)|
|Miscellaneous||Majokko Mirakurun • YuruYuri X • Miracle Girls Festival • Release the Spyce: Secret Fragrance|