A result of the experiment of the garde to the normal human combined with the avian wings on their backs resized to match human’s weight, they ended up having the ability beyond flying with wings, which are solid touch to the clouds, which explains their ability to build houses out of cloud, and an enhanced stamina, double the land bonded humans’. The rest up to today are natural breed, no more are the experiment results because only the ancient times garde can perform such thing.
NOTE: “Icari” for plural, used the name cuz I’m just sick of people using the term “angels” and because Icarus is the only very notable myth character that depicting a human flying with feather wings (tho just wax and feathers composition on arms), AND I can’t just simply use the term “Horusian” (I’ve watched CW’s DC series recently and thinking of Chay-Ara & Kufu cuz they worship Horus) cuz I won’t introducing Horus to this humanized universe of MLP