Seto no Hanayome

Aired: 2007

Middle schooler Nagasumi Michishio nearly drowns in the Seto Inland Sea but is saved by the mermaid girl San Seto. By mermaid law, any human who learns their identity must either die or marry into the family, so Nagasumi and San become engaged. San, daughter of a Seto Inland Sea yakuza family, transfers to Nagasumi's school, leading to a slapstick romantic comedy with her mobster father and a colorful cast of characters. Based on Tahiko Kimura's Gangan WING manga, produced by GONZO and AIC across 26 episodes.