"Isekai Quartet" is an anime series that brings together characters from various popular isekai anime, including Re:Zero, KonoSuba, Overlord, and The Saga of Tanya the Evil. The show features these characters in a school setting, where they interact and engage in comedic situations, blending their unique personalities and abilities. The series is known for its lighthearted tone and humor, appealing to fans of the original shows. Each episode typically showcases the characters navigating everyday school life, while also referencing their original storylines, creating a fun crossover experience for viewers.