So Stuart Hatford is a part of his own mafia in Britain, yes? While Stuart and Mary's parents were never mentioned in the story, this does make one assume that Mary was born into a crime family of sorts then. Thus, through connections, she ultimately fell in love with Nathan Wesninski, also a part of his own mafia.
Now the big question is: who benefitted from who? You could say that Nathan was more powerful in the beginning, being connected to the Moriyamas, but are we sure that that happened before he got with Mary? What if he married her to get more connections. The Moriyamas are aware of the Hatfords after all, and based on what we know about Nathan's circle: he is simply the Butcher of Baltimore, and he has a couple of lackeys. Stuart, however, seems to have more people. He brought a SWAT team level group to Baltimore to kill Nathan, and that is after he got permission from the Moriyamas to do so, after all. Then later, when Neil decided that he needed to get rid of Grayson, it only took a couple calls to his uncle and it was handled swiftly, and no Moriyama protested to that.
So what if Nathan married Mary for these connections to the Moriyamas and then later decided to abandon all pretenses once he got what he wanted? Stuart was clearly concerned about his sister and nephew to some degree, and yet Mary did not run to him, not even when years had passed since she stole Moriyama money from Nathan and took her son and went. It's all very intricate, and it makes the Wesninski and Hatford prior connections all the more interesting. So much more entertaining to think that Mary was the one with the power at first, and then the moment it got handed over to her husband she lost everything. Also makes Neil's childhood all the more saddening. He was just a baby throughout all of this.
