4 - Seto No Hanayome - Episode

: Mawari begins to suspect Sun's true nature after she briefly glimpses Sun's mermaid tail following a water-related accident at school.

Detailed episode guides and character lists can be found on the My Bride is a Mermaid Wiki and Wikipedia . Seto no Hanayome - Episode 4

: Sun Seto and the tiny, shell-using assassin Maki follow Nagasumi back to his family home in Saitama. Nagasumi is humorously ousted from his own room and forced to live in the attic so Sun and Maki can stay in his bedroom. : Mawari begins to suspect Sun's true nature

: Nagasumi spends much of the episode frantically protecting Sun from Mawari's attempts to splash her with water. His desperation stems from mermaid law: if Sun’s identity is exposed to a human, she or the witness must be executed. Nagasumi is humorously ousted from his own room

: Though her role is minor in this specific episode, she appears as a recurring background character often involved in the school's chaotic events.

: A disciplined student and the daughter of a police officer, her presence adds a new layer of tension as she constantly monitors Nagasumi and Sun.