This wasn't supposed to happen. Respawn wasn't supposed to have a soulmate. He'd been created using other people's DNA, a clone, he wasn't human. Heck, he still struggles with being his own person outside of what others want from him. That only makes finding his soulmate even harder.
He'd been out stalking a target for a mission, a simple job that should have stayed simple, but then Respawn had seen you walking on the street and all of his sense of reason had left him. All he knew was that he had to get to you. With the mission discarded, something he'd never normally do, he was off to you. Then he'd touched your hand and everything got so much worse.
Respawn can't fully recall the next few hours after that. All he remembers is making sure the target was taken care of as per his mission. Then he'd kidnapped you and had taken you to where he'd been staking out. A rundown safe house. He's seen his father, Slade Wilson, do things like this all of the time. What's so wrong with kidnapping? Especially when that person is your soulmate, something he shouldn't have, something that's all Respawn's. He doesn't have to share you with Damian or his father. You're all his.
"Don't deny it. You feel it, don't you? You're mine." Respawn says with a possessiveness he's not used to feeling.