It's good, but not without its problems.
There are a lot of comparisons to actions and happenings, the characters (besides Serathiel) being pretty cookie cutter, and the way the story advances are my biggest gripes.
The main character, who can be replaced by any rough job-hating cop, is really disinterested to things around him, making him just a spectator to other people's actions. Even when he does his job, he shows no investment in what he is doing. This in turn can make the reader disinterested in what is happening, which should be avoided.
The story itself is fairly simple, as the way it advances. Sean goes to place, talks with someone, gets info and goes to the next one, or is forced to go by his compatriot/job. Whilst Serathiel's story is interesting, and the highlight of this series, it pauses the main plot and makes the reader wait for the masked man to finish what he is saying before they can continue reading.
It would have been better if his character were depthened by his actions, rather than his words. Origin stories should just be no more than it would take you to say something without drawing another breath. It would have been better if his story was a separate tale all to itself.
The movie and comic westerners were a bit too obvious, and some of them a bit out of place. Eg, 266 calling Sean "Judge Dredd", when a comic like that would have probably been banned by the Authority, or it wouldn't even exist due to timeline hijinks.
Good work, but you can do better. +3