When Marion meets Illya in the episode "The Quadripartite Affair (S1E03)", she is attracted to his aloof manner. Illya is too occupied with protecting her, until they are captured and the rock of ice starts melting.

They rekindle their romance in "The Giuoco Piano Affair (S1E07)".

Illya: "You have to learn to ignore me. Pretend I'm part of the background. Just another rock or a tree."

Marion: "All right. You're a rock."

Marion: "Illya?"

Illya: "Shh."

Marion: "But I'm so..."

Illya: "Please. I must think. There has to be some way out of this."

Marion: "But there just isn't, so can't we just talk?"

Illya: "Not now. Just pretend I'm not here. Part of the walls."

Marion: "That's what you are. All right. Pretend you're part of the walls. Or a lamp or a chair or a tree or a rock. But just for once... just once, couldn't you pretend you're a human being?"

Illya: For a few moments, then, let us pretend I'm a human being."