In that case feel free to leave it as "Oh! Yes! I remember you!"
But Roggie just chucked a guy out the window and is in a bad mood. He's a balrog. Though he's merely misunderstood, that doesn't mean he doesn't have a fiery temper.
"What can I do for you" is a lot less likely right now than "Go away before I cook you into something that
needs the salt." I figured "So what?" was a bit more diplomatic.