Chris first decided to change himself, making himself as muscled and attractive as Matt while being sure to avoid any mental changes. He liked his mind just the way it was, thank you very much. After looking everything over and deciding he was satisfied with it, he got to work on Matt.
He briefly considered just restoring him, it could be a laugh to let him see what he'd been up to as a himbo, but decided against it. After all, Matt wanted to be this way, so who was he to drag him out of his ideal state? Though he would have to make some changes of course....
He'd keep Matt mostly as he was, he seemed happy enough in his current situation, he thought as he looked over at Matt still idly whacking off. He would up his submissiveness though, and make sure he was loyal to Chris specifically. God, the thought of having a loyal sex freak like Matt to order round was already making him hard. Following on from that thought, he decided he'd go even further and use the Chronivac to make Matt his legal slave. Matt clearly wanted to be freed from the burden of thinking for himself, so he'd surely be happy enough being ordered about by Chris. Well, he definitely would be once Chris had finished with the Chronivac anyway.
Chris started typing in the changes he desired; Matt would be his legal slave, and reality would be altered so that everyone would be fine with that arrangement. He let the Chronivac sort out the details of how exactly that would happen, it didn't really matter in the grand scheme of things. With the reality change along with the personality change Matt would be incredibly loyal towards Chris, seeing him as a mixture of best friend and lover as well as master. And he increased his submissiveness to that point where Matt would actively enjoy obeying Chris' orders. So really everyone would be happy with the new state of affairs, Chris thought. He made sure that everyone would remember the new reality as having always existed, except for himself. He wanted to keep the knowledge of having made stud boy Matt into his slave, it'd add an extra level of excitement for him. To round things off he made Matt a few inches smaller, it wouldn't do to have his slave towering over him after all.
He pressed confirm on the changes, and the world shifted around him. He instantly grew and bulked out, glancing in the mirror next to him he was now a muscled stud equal to Matt, his face looking much as before but more masculine, more defined and with everything straightened out a little. He tried out a few test flexes, feeling the power of his new muscles, then turned to look at Matt, smiling as he watched the changes take place.
Matt's head was full of a harsh buzzing noise for a moment, but the buzzing quietened when he looked at Chris, his.... owner. New memories flooded into his mind, his brain accepting it without any resistance. In this new world Matt and Chris had been firm friends since childhood, even if they'd been pretty different personality-wise. Chris had been the golden boy who'd been equally successful on the playing field and in the classroom, and while Matt was gym buddies and together on the football team with Chris he'd never bothered with the studies at all. In fact Matt neglected his education in favour of sports and generally taking care of his appearance to the point where he failed his graduation exams.
In this world people who failed to graduate school were considered unfit to be full members of society, so they were enslaved and given to a master who would take responsibility for them. Happily for Matt his friend Chris agreed to become his owner which saved him from being sent to a slave auction. Matt was happy with the situation, he ended up with a nice owner, plus Chris was smarter than him anyway so it made sense that he do the thinking for the both of them. Chris didn't give him too many duties anyway, Matt spent most of his time working out in the gym and styling his appearance so he looked good for his owner. And of course he had to service his owner in bed, something the two of them greatly enjoyed.
As Matt was thinking about this he didn't notice himself shrinking a few inches, so he was looking up at master Chris. He also had a PROPERTY OF CHRIS MARSHALL tramp stamp appear on his body, slaves had to be visibly marked so everyone knew who they belonged to. Master Chris liked having Matt wear skimpy clothing so his tattoo was visible, but Matt didn't mind. He found it hard to explain why, but he just felt... safe being owned by Chris, and he really enjoyed being ordered around by him. He saw that master Chris was smiling at him for some reason, he felt butterflies in his stomach at the idea of his owner being happy with him. He wasn't sure what they'd been doing but looking down at the impressive boner stretching his master's pants he had an idea of what they would be doing. He wanted to go to town on that amazing cock and feel his master's muscles all over, but master Chris didn't like him making the first move without being ordered to so he stood patiently, waiting for a command.