The name "Redcross Knight" is actually just a nickname (given because his symbol was a red cross that eventually evolved into the flag of Britain) for St. George, a historical figure whose life is enshrouded in legend. St. George is known in art and tradition as the slayer of a great dragon; hence the title of issue #37, 'St. George's Syndrome' (In which Boy Blue slays a dragon in the homelands). The Redcross Knight appears in the Keep at World's End, where he is the second to last fable to die in its defense. It can be considered ironic that The Redcross Knight (aka: St. George- the dragon killer) is eventually defeated at the Keep by one of the Advesary's dragons. As Boy Blue says, "He lasted for over an hour and I began to believe he'd win all on his own. Until they set the dragon against him. It's said he killed a dragon once. But not this time."
Later, he appears again helping the Best rack down the Lamia.