Isekai Quartet 2 already introduced the Rising of the Shield Hero characters, but it turns out they aren't the only isekai light novel characters to guest star in the expanded universe of Isekai Quartet. Seiya and Ristarte have a brief cameo in episode 11, where they are shown poised to join in on the school festival fun. However, Seiya's overly cautious personality may just get in the way...

The inclusion of the two Cautious Hero: The Hero Is Overpowered but Overly Cautious characters was announced after the fact by the Isekai Quartet official Twitter account. It announced that Seiya and Ristarte voice actors Yuichiro Umehara and Aki Toyosaki had joined the cast, and confirmed with a screenshot that Ristarte did indeed have a brief cameo in episode 8 prior to her episode 11 appearance.

The episode also features an endcard illustration drawn by original light novel illustrator Saori Toyota. The image shows the two "hopeless goddesses" Aqua and Ristarte buddying up while Seiya lifts weights with Ainz.

The television anime adaptation of Light Tuchihi's Cautious Hero: The Hero Is Overpowered but Overly Cautious novels premiered in Japan on October 2. The story begins when the goddess Ristarte summons a hero to help her hard mode video game-like world. The hero, Seiya, is exceptional in every way, but he is incredibly cautious. He does things like buy three sets of armor (one to wear, a spare, and a spare for the spare) and go full power against weak slimes (just in case).

The Isekai Quartet 2 anime series premiered on January 14. The anime is a crossover series between the Re:Zero, Overlord , KONOSUBA, and The Saga of Tanya the Evil franchises. The first season premiered in Japan in April.

Source: Isekai Quartet's official Twitter account