Adeline Quarles

Adeline Quarles is the legendary nymph who is the Keyblade Wielder of the Icy Butterflies, Kieran, Sora, and Summer's long-lost elder cousin, and the long-lost close friend of Aqua, Terra, and Ventus.

She is voiced by Elizabeth Gillies.

Personality
Adeline is the legendary Keyblade Master of an extremely powerful nymph, bound to the magical worlds, as she was "killed" (actually disappeared) sixteen centuries before the beginning of the events of the series when she was separated from a young Kieran, Sora, Summer, Kairi, and Riku. She returned after Kieran and his friends defeat Xehanort.

Adeline demonstrates her resourcefulness; solving Kieran's problem with finding a secret location by giving Kieran her Keyblade in Kieran’s Adventures of SpongeBob SquarePants featuring Nicktoons: Globs of Doom. With it, Kieran would be seeing through Adeline's eyes and see their flashbacks as he remembered it before they were separated from each other.

Despite the fact that there is a constant aura of mystery and secrets about her, Adeline is a kind and loving woman, and a devoted cousin to Kieran and Sora (she willingly sacrificed herself for her younger cousins) to whom she acts as a guardian spirit of sorts, guiding them through their troubles with both their magic and adventures, telepathically communicating with them if they have any trouble.

Adeline is not quite emotionless, though often she is portrayed as serious, this is due to the fact that she is only seen during more dire situations, although, Adeline reveals her more playful side as she acts as a ghost scaring Donald and in most of the appearances she made, she was quite cheerful and was smiling. After Kieran frees a fish he was forced to eat, Adeline appears and tells Kieran that when he was alive he also had to eat raw fish and that it tasted horrible.

Due to her beauty, Kieran and many of his friends often describe her "the most, extremely beautiful.", even Dark Kieran and the DKE villains.

Glaceon
Glaceon is one of Adeline's pets/Pokemon Partners.

Leafeon
Leafeon is one of Adeline's pets/Pokemon Partners.

Floette (Blue Flower)
Adeline first met Floette during a storm and befriended her. She then trusts her to help Kieran, his friends, and even his enemies to act as a guide for them to help them find her.

Ventus
Ventus is one of Adeline's close friends.

Aqua
Aqua is one of Adeline's close friends.

Terra
Terra is one of Adeline's close friends.

Trivia

 * Ventus has a crush on her.