After a moment, Zerxus nods - but he doesn't start moving again.

Instead, he reaches out a hand to clasp Steve's arm, and it alights again - but the flames are white now, and as they dance up Steve's arm it's with a soothing warmth.

"You have his protection. This is mine, if you accept it." The spell nominally requires a willing participant, but he could force it. He won't. "As long as you're within sixty feet of me, it will be harder to hurt you, and easier for you to resist anything cast on you. Even if it's me, or him."

It would only last an hour, cast by a mortal. He's far beyond that now.