Ikki is actually a Gravity Child, a Brain Charger, or something else entirely.
Think about it. He has ridiculous talent with A-Ts, and he has the same last name as Dr. Rinta Minami, the person who created The Gravity Children and
The Brain Chargers. Ikki even lived with Rinta before he was left in Rika's care, causing him to be raised alongside three Gravity Children by a former Queen. The whole purpose of the Brain Charger project was to create a human who had the desire to fly, and Ikki wants to fly more than anything- despite being a Blood Knight
who resorts to violence before anything else, he's uncomfortable about using wings to fight because they should really be used to fly higher. And then, near the end, when Ringo whips out the Storm Regalia and activates it, Dr. Minami screams "The Storm Regalia was for him! I didn't design it for this!"
Dr. Minami didn't
make the Storm Regalia, though, Kururu did, which means that he came up with the original concept, possibly leaving some kind of blueprint in Electric Brain Space that Kururu unconsciously followed, and that he designed it for Ikki.