Who was the god harmachis?

Harmachis is the name of Horus when he was first born - as a brother of Osiris, Isis, Nephthys, and Set. Later on, Horus is also described as the son of Osiris and Isis. Since it is confusing to have one god who was born twice, and is seemingly his own uncle, it became customary to call the first incarnation of Horus "Harmachis" and the second one "Horus."