Herobrine's Mother is the mother of Herobrine and an evil entity, just like the latter.
Herobrine's Mother look very similar to Herobrine AND Steve, with clothing of the same color as her son and blank eyes like him. However, she wears more girly clothing, and has long chocolate-brown hair. Her color palette is the same as Steve's.
Herobrine's Mother is an evil and abusive entity. She hates her son Herobrine and constantly embarasses and abuses him. She thinks her son is a failure, and enjoys his suffering. She is vicious and terrible to people. However, she often falls in love with strangers, like Billy The Builder.
She might be the mother of Notch, but that isn't confirmed.
Mother of the horrifying Herobrine who is strangely attracted to little children.