S3E06 The Mermaid of the Abyss!

The Mermaid of Abyss! (深淵のマーメイド！ Shinen no Maameido！) is the sixth episode of season three of the Free! anime and the thirty first episode of the overall series. It aired on August 15, 2018.

Synopsis
Hiyori Tono attempts to cheer up Ikuya Kirishima by recalling memories of their early days, but ends up challenging him to stop obsessing over Haruka Nanase. Meanwhile, Misaki Kuramoto, one of Makoto Tachibana's swim students, questions Haruka about why he only swims freestyle and Ryuji Azuma, a mysterious man from Hidaka University, makes his move to become Haruka's private coach.

Source: Wikipedia, with author's permission.

Characters
List of characters in order of appearance: