A knight of the Rock in the years of the Dance of the Dragons, of an uncertain branch of the lions of Casterly Rock. In the years after Lord Jason's death he commanded a Lannister naval attack against Lord Dalton Greyjoy on Fair Isle in support of Lady Johanna's bid to recover the isle from the ironborn; the venture failed and Ser Erwin was killed in the fighting, his loss numbered alongside the deaths of Lords Prester and Tarbeck.
