When Harold said chain, this wasn't what John had in mind.
John's mental image was thick metal. What Harold just closed around his neck is indeed metal, but spun thread-thin. John is terrified he'll tear it apart if he moves too carelessly.
"That's the idea, isn't it?" Harold murmurs when John mentions this, half-joking. "The chain isn't what's keeping you here."
"Please," John says, suddenly desperate and afraid, moreso because he has no idea what he's afraid of or what he's desperate for.
With a grave expression, Harold says, "No." He sounds regretful. "You must realize, John. You're immensely strong, and as much as I would love to relieve you of the burden of responsibility - sometimes I must give you beautiful, fragile things, and hope you will care for them."
John clenches his hands into fists. He almost wants to rip the chain on purpose, just to be done with the horror of the idea. "Not like you to set me up to fail."
"I'm not." Harold sounds frustrated. John is almost glad, in the same way a trapped animal is relieved to see the knife coming down. "I have no choice, John. If nothing else, I have to trust you with you."
The tricks minds play are so odd. John knows that the chain is light as a feather, that it can't actually have gathered enough mass to suddenly lie heavy on his neck, and yet.
Harold takes John's face in his hands, forcing him to look Harold in the eye. John squirms weakly. "Do you understand me? You are beautiful, and fragile, and I have no choice but to trust your care for yourself."
Protests mingle together, garbling on John's tongue. "Are you saying I'm not tough?" he finally manages.
Harold pulls the chain, hard and sudden. John loses his balance. He catches himself and settles on hands and knees, with Harold holding on to the leash around his neck. It's something he's wanted so much, but he's never imagined arriving at it like this.
"Fragile things can be tough, too," Harold says, holding up his hand. "This alloy can be cut easily, but you'll find its tensile strength is quite high. Some materials are funny that way."
John closes his eyes and hangs his head. Harold shifts so that John can rest his forehead against Harold's leg, Harold's other hand clutching possessively in John's hair. "You've made your point," he says, hoarse. "I'll use a safeword."
"Thank you," Harold says. He sounds relieved, too. John circles Harold's ankle with one hand and holds on.