The spring 2019 anime project Isekai Quartet that focuses on the Overlord and Saga of Tanya the Evil characters wrapped up back then with word that a second season was coming. This season will, however, be adding characters from The Rising of The Shield Hero within it and we knew from earlier reporting that it would be a winter 2020 show. now, the official site has updated to reveal a January 14th, 2020 debut for the series on Tokyo MX and rolling out to a few other places as well.
The series has Minoru Ashina writing and directing the project with character designs by Minoru Takehara, who also serves as the chief animation director. Studio Puyukai is handling the animation production.
Plot Concept: The project will be a crossover anime featuring characters from the Overlord, KonoSuba – God’s blessing on this wonderful world!!, Re:ZERO -Starting Life in Another World-, and Saga of Tanya the Evil franchises. A mysterious button suddenly appears one day, and characters who press it are taken to a new world to gather.
— 『異世界かるてっと』公式 (@isekai_quartet) December 6, 2019