Esin

Second known incarnation of Uranus, foundling of an as-of-yet unnamed nomadic tribe in the Empty Quarter of the world Chogoris, is it not known exactly how old she was when her tribe approached Jaghatai Khan but she was already considered that tribes best horseman and was chosen to challenge the Khan to see if he was worthy for her tribe to join his cause.

At least, that was the idea, as to Jaghatai's displeasure and Esin's amusement that unnamed tribe hadn't really believed the rumours of a Primarchs height, so hadn't accounted for him not being able to ride the horse they had selected for him.

This, however did not prevent the Khan and Esin becoming as close as siblings despite there being no blood relation between them in the years after.

Esin was killed at the beginning of the Heresy when the vessel she was on was destroyed by the attack of a suicide bomber that snuck aboard.