An official website for a mini crossover anime has been launched. Titled Isekai Quartet, the anime will consist of mini characters from these four anime series: Overlord, Kono Subarashii Sekai ni Shukufuku wo!, Re:Zero kara Hajimeru Isekai Seikatsu, and Youjo Senki, and is slated for next spring.
A mysterious switch appeared one day. When pressing it, they were sent to a different alternative world!! There are also characters from other alternative worlds gathered together...!?