IMPORTANT NOTE: He only appears in the anime verison, and DOES NOT appear in the manga.

Ancestor of Winner and Victor Sinclair.

The Sinclair's family history has written him down as the man who was seduced by the vampire, Elda Marker, grandmother of Karin. He was both a poet and a writer who wanted a world where humans and vampires could co-exist without fighting.

(Taken from Wikipedia.org)
(Edited by Tiamat)