Cleos Umber

Cleos Umber is an unseen character in Game of Thrones. She is not expected to appear in the series, being long dead by the time it starts.

Background
Cleos married Vivian Cerwyn, with whom he had a daughter, Katrina. Katrina later married Joseth Umber and had two sons, Maynard and Cedric.

Season 1
He is mentioned in The Lineages and Histories of the Great Houses of the Seven Kingdoms.

Reference

 * "A Golden Crown"