Mr. Merman, also known by his stage name Yuhuo, is a young merman rescued by Song Wudao from traffickers dealing in rare races. He was kept in extremely harsh conditions by his slave trader, confined to a damp, dark basement with water changes only once a month. The bottom of his aquarium was covered in greasy residue, forcing him to soak in moldy, foul water day after day. His skin had become dull and lustreless, and he suffered from severe skin diseases. What kept him alive was a beach electronic music festival advertisement featuring a photo of the ocean, representing his longing to swim in the sea. Song Wudao promised not to harm his body or force anything upon him, only requesting that he record songs in exchange for residency rights on a deserted planet purchased as a base. Thanks to miraculous medicine brought by Song Wudao, his skin disease mostly healed, though his hair remained bleached white and his eyes stayed red from untreated inflammation. Mermen are highly sensitive to biological emotions, and when Song Wudao mentions his sister, the surrounding seawater transforms into a gentle sweetness that only mermen can detect.
