Mack is a rogue cop from the year 2278, who left the corps after he saw how corrupt and bigoted it was and how it did nothing against the mega corporation, Raycorp, founded on the 2010's by Steven Raynott. The corporation had humbles begginings, but as soon as Steven retired from his position as CEO, it all went downhill from there. His son, Javier, was a considerably more greedy individual with a lot more selfish intentions for the company, for example violating the human rights for cheap labor, and doing experiments with those same humans for the "PHB Project" (see Garcia's bio).
Ever since he was a little child, he admired the police force of New York. He liked the idea of protecting others and having a whole force to do that with. Ever since he was a little girl (yes he is trans), he admired those people and wanted to be a cop.
He was a straight a student on his school and after, he got to a cop academy. He was built like a wall, he was super strong and was a example on the academy. He got a whiffy sensation from some of the classes that he saw, that some of the veterans cops said things like "turn off your bodycam" or them saying that "they are above the law" but he chose to ignore that because he was excited to be a cop.
After he graduated, he got a police department on the city district and was partnered with a old time policeman. The old policeman was normally abusing his power to do illicit stuff and lock up people who didn't do anything wrong and incriminate those same people to lock them up for even more time.
There was one time a black guy was smoking outside and the old policeman (lets call him Kyle) stopped all his tracks and started to interrogate him for no real reason. He got arrested and Mack tried to talk down Kyle for locking down a person for no reason at all. Kyle tried to explain that he was a gang member and he wanted to get some info from him, but Mack also counter that point by saying "if he was doing nothing ilegal, then you have no right of arresting him". At the end, the gang member was released with no charges. Before he left, he said to Mack "your place is not here, man".
Kyle multiple times brutalized citizens with Mack needing to stop him, and Mack had his hope on the police force slowly decreasing. There were times that Raycorp was very clearly violating human rights on their experiments, but Kyle and the whole police district in fact was trying to get him to stop investigating Raycorp.
For at least a year and a half, Mack reported his heinous actions to the public and tried to get him fired. At return, the police department fired him instead. The police captain said in Kyle's defense "that he is old and he is almost retired." with Mack saying in counter-point that "someone so decrepit and with misusing their power that they were given to protect people to their own twisted ends shouldn't be given that power at all" but the captain didn't listen.
Mack was distraught and didn't know what to do, and a gang member he saw some times on his one year of policeing saw him like that. they had a talk. Mack explained what happened to him and that he didn't understand what he did wrong. What the gang member said to him afterwards changed his perception of everything:
"Look, this always happens to people who tries to be good cops on there. They try to be 'on the line' and 'be good', and they always get layed down for trying to do the right thing. I lost some friends because of those assholes, you didn't do anything wrong. It's just impossible to do the right thing when the system makes sure that the right thing is not the way that things are done. But if you really want to do the right thing, come with me".
They go to help communitties in need, donating to charities, and helping people in general. That made him feel more like he was helping more than he ever felt he was in the police force.
Even then, he wanted to take down Raycorp and their procedures, so he makes an unofficial detective office that he does his stuff alone.
He is determined on making the system better and taking down Raycorp would one of the best ways to do that, as he research them and they seem to dominate the government to do their nefarious things and being above the law. Although they aren't the only thing wrong with the system, they are a good start to make it better.