Aile

Airu is the Emperor Mateus' mother. While she doesn't appear in Final Fantasy II proper, she has a role in its Japan exclusive novelization Final Fantasy II Muma no Meikyū.

Story
The novel states that Palamecia is cursed with demonic influences that corrupt its emperors. Satan, desiring to rule the world by human proxy, turns men into malicious masterminds by using everything at its disposal to pollute their thoughts with its malice. Satan originates all the way from the beginning of the world when it became trapped within the indestructible "Stone of Iludia" and swore revenge by any means. After ascending to the throne, Mateus exiles Airu to the deserts of Palamecia and yet she still spends her life trying to find a way to save him. During the novel, Airu and Minwu team up to find a crystal, which can purify the land. It ends up being too late to save Mateus, but it helps to bring peace to the world.

Trivia

 * Since the novel was only released in Japanese, it is unknown what the proper Western-alphabet spelling of Airu's name is. "Airu" is the direct romanization of her name in katakana, but other spellings such as Ailu, Ayru, Air, etc. are equally acceptable in the absence of any official confirmation.