Haida is a character from the anime Aquarion: Myth of Emotions, specifically appearing in the Kako Shinwa-hen, or Past Myths Arc, which depicts events that took place twelve thousand years before the main story. She is identified as the past life of the present-day character Rimiya Tsukishiro. Haida is a member of a mythical race of winged people who were blessed with emotions by their goddess, Mulua Satene. She is portrayed as the younger sister of Sedona, the Priest of the Moon. Her world and her relationships are defined by the complex hierarchy and duties surrounding the goddess and the three priests who serve her.

In the distant past, Haida is portrayed as caring and deeply concerned about the well-being of others, particularly her sister Sedona and a set of mysterious twins who came from outside their land of Nakar. Her personality is defined by her emotional attachments, which ultimately drive the story's central tragedy. She fears the loss of those she loves, specifically the separation from her sister and the departure of Nanook, the Priest of the Sun who is in love with Sedona. Her motivations are rooted in a desire for the collective happiness of this close group, leading her to take desperate action to prevent a change she believes will tear them apart.

Haida's primary role in the narrative of the past myth is as a catalyst for a pivotal conflict. The goddess Mulua Satene had chosen Sedona to become the next vessel for her divine mana. When the Sun Priest accused the Moon Priest of causing a mana pollution, Haida committed a significant act: she intentionally discolored her sister Sedona's wings. Her motive was not malice but a wish to prevent Sedona from ascending to godhood, which would take her away from Nanook and disrupt the bonds between them. While Haida saw her action as merely dyeing the wings, it was interpreted by others as a sign of corruption. This event became a breaking point, leading Nanook to defy the goddess and the established order to protect Sedona. In this way, Haida's emotional decision, born of love and a fear of loss, sets the stage for the great conflict of the mythical era.

Haida's most significant relationship is with her elder sister, Sedona. Her actions are motivated by a desire to keep Sedona close, highlighting a deep, familial bond that she is unwilling to sacrifice to divine duty. This bond is so powerful that it echoes into the future, as the present-day reincarnations, Rimiya and Momohime Amaha, feel a strong, non-romantic familial connection to each other rather than a romantic one. Haida is also intertwined with the fate of Nanook, the Sun Priest who loves Sedona; her desire is for him to find happiness with her sister. Her development is tragic and essential; she is not a villain but a caring individual whose inability to let go has unforeseen and calamitous consequences for the world. This act of staining Sedona's pure white wings is her defining moment, transforming her from a concerned younger sister into a figure whose emotional choice leads to a legendary schism.

Regarding notable abilities, as one of the winged people of the mythic age, Haida exists in a world governed by emotions as a tangible power called Mana. Like others in her society, she is presumably able to receive divine protection from the goddess Mulua Satene, and her actions have a direct impact on the spiritual and political order of her world. However, no specific unique powers distinct to Haida, such as combat skills or unique magical abilities, are outlined in the available information. Her most impactful action is the physical act of discoloring her sister's wings, which carries immense symbolic and practical weight within the story's lore.