Remember that Embodiment Of The Wicked symbolic Art series? Yeah, I really wanted to put Denis and Sebastian in it.

Symbolism: Sebastian has one arm behind his back to give Denis the Illusion he won't lay a hand on Denis for evil intent. The other arm has it's hand on his shoulder to seem friendly, but it's a lie. The censored eyes are a symbolism of how you can tell a lot of someone because of their eyes, Sebastian however has his eyes covered to hide his identity along with a small smile to seem like a friend. 

Denis has been paranoid due to certain events and is scared by this stranger getting up close and personal which explains his worried expression.