Mirra is tall, slender. Light armor on the shoulders, bronze gauntlets, and an aerodynamic, feathered helmet. The helmet is bronze, shaped like the head of a bird of prey. Elbow-length brown hair, with two long braids, also adorned with long, blue feathers. Short, dark blue cloak wrapped around armor and helmet.
Rukh is made of interlocking plates and gears of Celestium, a refined Oocca ore. Leather harness and saddle. Wingspan of thirty meters. Mechanical, shrieking siren call audible relative to altitude.
Blue-feathered mantle (armor and cloak) grant agility, high "gliding" jump, speed (Roc's Cape and Roc's Feather). Megafauna avian familiar shares telepathic bond. Riding saddle. Dominion Rod ("rod of the heavens"), granted by the Oocca to animate Rukh.
Mirra and Rukh form a team in combat. In the air, Rukh exerts influence over surrounding weather patterns to create favorable winds; on land, he is fast and deadly with razor talons and beak. Mirra performs mild healing magic, channels electrostatic pulses through Rukh into Dominion Rod.
Long-distance flying exhausts Rukh, tending towards over-ground running. Discharging accumulated lightning bolts will leave Rukh grounded temporarily, and Mirra will lose Dominion Rod control.
When the Ancient King of Hyrule sought to protect the Triforce from evil, he and the Sages sealed it away in the Sacred Realm, where it could only be reached by one who possessed Courage, Wisdom, and Power in equal measure. To try the Courage of all interlopers, the Ancient King and the Sages beseeched the Sky People, who had created the Hylians, to appoint a Guardian of the Sacred Realm. The Sky People's response was the avian war machine Rukh, the Thunderbird who would test the mettle of any warrior.
To pilot Rukh, the Oocca would adopt one Hylian daughter from birth, raising her in the arts of the messengers from heaven. In her era, Mirra was chosen before birth to be the master of the Guardian bird. Her soul was sundered in two, part left in her Hylian body, part fused into the mechnical body of the Thunderbird. They move, breathe, and fight in perfect synchronization, at all times prepared to lay down their one life together in defense of the Sacred Realm's delicate balance.