Mission Mermaiden - Hasumi And The Deep Sea Sis... -

It started with a rhythmic thrumming in her chest—a "Deep Sea Signal" that only she could hear. Following the frequency, Hasumi dove from the pier, expecting the shock of cold. Instead, her skin shimmered with a bioluminescent film. Her legs didn't kick; they fused into a sleek, midnight-blue tail tipped with silver.