Origin
Not much is known about Mark’s origin, before he and his sister Anya joined a group of survivors of the Crossed epidemic.
His sister died while giving labor. Forced to continue, he quickly burried his sister. Later, when a group of Crossed came chasing them, Mark saw that one of them had dug up his sister and was dragging her with him. Overpowered by the group of Crossed, Mark became one of them.