It's a good opportunity to claw back his composure, at least. Zerxus only turns when Steve speaks, and for a moment he can't grasp the words because -

"Of course you look good in blue." There's a deeper ache beneath the wry grumpiness, but he's trying to get focused again.

"There's nothing else in the contract, but..." Was there something he missed, before he had the right context? It's easy to see the angle Asmodeus was working from, now - enforcing a need for trust and reliance - but does that change anything?

Finally, with a slow shake of his head, "No. ...And if I ever feel the need to make another one, I'll talk to you first."