Amame Doi (土居 亜麻芽, Doi Amame) simply known as Mermaid (マーメイド, Māmeido) in the first game, is is a minor character in both both AI: THE SOMNIUM FILES and the Lemniscate YouTube series, and a major supporting character in AI: THE SOMNIUM FILES - nirvanA Initiative.

Amame is a third-year at Sekiba High and a member of the dance club. She's good friends with her club mates Iris Sagan and Kizuna Chieda, as well as with Mizuki Okiura and Ota Matsushita. Amame works part-time as a maid at Sunfish Pocket, and she has a sharped-tongued side to her. She occasionally goes on haunted tours and UFO sightings with Iris, Mizuki, and Ota.

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