In a sense TPS tells the tale of Handsome Jack’s turn to evil. He’s certainly done some evil things before then. But perhaps he wasn’t completely turned until the events of TPS. Either way he was certainly power hungry. Moxxi could see his dark side and tried to kill him before it went any further. By the end of the game we see Jack has embraced his dark side and now has the means to start wiping out people and the control.
I feel like the claptrap DLC tells an almost parallel story of claptrap’s internal struggle. He seems to have his own ambition to rule the galaxy or pandora (and he tried once before in BL1). And he comes dangerously close to taking over hyperion via the H source. But claptrap has his moment to betray everyone and he says no to the darkness inside him. His shadow.
I clicked on the thread below thinking he had started a version of my topic before I could. Obviously they are different.
Continuing the discussion from Handsome Jack Claptrap: