Sean Bean was also from that alternate universe where Sheffield is the 51st state of the USA in Missing.

In the books anyone can be made a knight by another knight. So maybe their father was a minor knight, hence the same coat of arms? I suspect there is a detailed wiki explanation, but if I look for it I might never escape.

Well, that's Tumblr for you. You can really replace "Sandor" in that sentence with any even vaguely villainous character ever. Oh, to live in the Tumblrverse, where everything can be solved by hugs and teddy bears.