[ Definitely a former knight, Geralt decides. He has his household's genuine respect.

He gets to his feet, pacing a little, gesturing as he explains. ]

Wraith — a type of ghost, but ghosts aren't necessarily harmful. Wraiths are, and they don't stop. Something anchors their souls here, a negative emotion — hatred, rage. Envy.

[ He turns back to the young lord, crouching on the balls of his feet in front of him, ignoring the healer as he works. ]

They can be dispelled, but only temporarily. Key to driving it away for good will be figuring out what binds it here and destroying that binding. Could be an object; could be something as abstract as an oath.

[ His eyes narrow a fraction, searching Sleipnir's hard. ]

Have to ask: how did you get away? Don't need to tell you that the rest of its victims so far were killed.