The best episode written by Kenji Saito is "Magus and Alchemist", rated 5/10 from 2 user votes. It was "directed by Hiroshi Nishikiori". "Magus and Alchemist" aired on 10/22/2014 and is rated 0.0 point(s) higher than their second highest rated, "Dream World and Sub-Administer".
It's summer. The gang's on a southern island, and there's cute girls in swimsuits abound. Arata's cooking yakisoba for some reason, but these things happen. The quartermaster is repairing the school that Arata destroyed in his collapse phenomenon. The girls enjoy a mixed-gender bath, and the demon lord candidate decides on a theme--control.
Director: Hiroshi Nishikiori
Writer: Kenji Saito
The girls are running in their exercise outfits, with the boobs swaying to and fro. Arata's heart races. Everyone's having great time, and then a ghost appears in the library. Arata and the gang go to check it out, and are forcefully transported to the "Eternal Library". There they find the lost Trinity Seven!
Director: Hideaki Uehara
Writer: Kenji Saito
The ultimate demon lord, Astral Trinity, shows up in the form of Arata with a grotesque new appearance. Hijiri appears as well, and the others discover that she is a high-level mage whose goal is to kill Arata and destroy the school.
Director: Hiroshi Nishikiori
Writer: Kenji Saito