Nina Nina (ニーニャ・ニーニャ, Nīnya Nīnya) is a ghost-like girl who dwells in the Roaring Cavern. She was a novice summoner from another island, but being horribly bad at reading maps, ended up at that island while finding ingredients for her teacher. She ended up in a boat and dozed off, and woke up as a spirit. She found out a Summon Creature named Passeau had stolen her body, and often comes back to taunt her with it. She had tried unsuccessfully many times to take back her body. She's a caring person and tries to be as helpful as possible to the main character. Eventually, with the help of the main character, she gets her body back from Passeau.
Nina is also a good friend to Borgim, and trusts the gargantuan summon beast to a complete extent in turn for kindness and bond they share. Because of this, Nina constantly worries about him a lot, and gently reprimands the protagonist of this in their debut. Nina and Orin are acquainted with each other and are constantly seen talking to each other a lot.
- According to Nina, she descends from a family of Summoners, and her surname is in fact "Nina". She also claims that her grandmother is responsible for her name as the latter believes that the name symbolizes future greatness, thus holding great expectations for the young girl.
- Nina is a novice member of the Cerulean Society (the Blue Faction), but when the protagonist interrogates if she knows who Magna/Toris, their Summon Beast, Nesty, and Amer are, Nina responds with a "no". It is highly likely that they were kept apart the entire time, Nina being the only one in her family to not know in their existence, and/or that the four aren't aware of Nina either.