[Kisses him back, at once not wanting to stop and at the same time too guilty to keep kissing him, even if he lingers and almost follows after him when Merlin pulls back. He closes his eyes, breathing out, moving his hands up to cup his face. Kisses him, too, briefly, although lingering]
He... pleaded with me. To let him go so he could follow him -- even though he knew it was just a ghost.