Isekai Quartet Announces Season 3, Adds The Eminence in Shadow
Isekai Quartet anime has officially announced Season 3 with a new addition: The Eminence in Shadow is joining the fray. The first visual has been released:

Overlord, KonoSuba, Saga of Tanya the Evil, Re:ZERO, and The Rising of the Shield Hero (joined in Isekai Quartet: Another World movie) are already part of the series, making it technically a sextet.
The first season of the Isekai Quartet anime aired in 2019. It had 12 episodes, each 12 minutes long. The second season followed the same format and debuted in 2020. Isekai Quartet: Another World movie was a sequel to the second season, and it premiered in 2022. Studio Puyukai animated all of these installments.
Crunchyroll is streaming the anime and describes the plot as:
The button appeared out of nowhere. There weren’t any signs NOT to push it…so the solution is obvious, right? Is it a trap or the start of something new and exciting? The crews of Re:Zero, Overlord, Konosuba, and The Saga of Tanya the Evil will find out when they go from their world to another and get stuck in…class?! See what adorable chaos they’ll get up to in this collection of shorts!
Source: Official Twitter/X
©Isekai Quartet/KADOKAWA Licensed by Funimation® Productions