House Blount is a small noble house of the crownlands, holding a few hides of land between the kingsroad and the narrow sea. Their arms — two black porcupines parted by a red bend sinister upon a green field — make them easy enough to mock at tourneys and no easier to dislodge from a defensive line. Among their few claims to renown is the white cloak: in every generation a Blount seems to find his way into the Kingsguard, where bristled service has always counted for more than glory.
In the years of Robert's reign that knight is Ser Boros Blount, a bald-headed bruiser of middling skill who took the white cloak under King Robert and kept it under King Joffrey. Jaime Lannister thinks him an adequate fighter and never more — and Ser Boros lives down to the assessment. At the opening of A Game of Thrones he rides north with the king to Winterfell; before the war is done he will be cut out of the white for cowardice and put back into it for convenience, in the way of all the Blounts before him.