The Luke and Diamondback convenience

Loved the show, but I couldn't get past this. So Luke breaks out of prison, ends up in New York, ends up in Harlem, which JUST HAPPENS to be where his half brother has been for years building a criminal empire. Convenient. Then Diamondback, full of rage, so blindly wants to kill Luke at any cost, destroying everything he's built over the years in the process... only AFTER the first episode he appears in. Before that he was just gonna let Cottonmouth handle it. Which doesn't really add up once we see just how deep the vendetta runs for him. Why would he have wanted Cottonmouth to handle it at all? I know it's no show ruining plot hole or anything, and obviously it's convenient to the story, but it's too convenient that it just plain doesn't really make sense.