Past-selves are one thing in terms of enemies. They make sense - they are just You cast in reverse along the same time-space environmental container. It's parallel selves who are a bit more tricky. They are not bound to the same lifeline You are situated within. Their stories and make up are unfamiliar; you can see the obvious trouble we can have when attempting to track them down. Knowing their motives may be key...Selfish - this particular parallel self chose happiness over spiritual servitude and it's time for him to pay the price.
Within the multiverse the distribution of quanta across different timelines is in direct proportion to the definitive nature of their locale. Less distributed quanta have a more fixed locale as they spread across less parallel realities and thereby they are more concentrated into a single, fixed reality bubble. To be the Uber-You one must channel these subatomic pixels into focus within the desired timeline. Alternative or parallel selves directly affect the focus of quibits within the particular biocomputer you inhabit in this reality. You can see how this may be troubling to a SysOp behind the command console of any given superorganism. To only be using 0.00001% of your subatomic system resources because some parallel self is running a shit ton of background processes can be a harsh reality to come to terms with. It leaves you feeling cheated, what the fuck is this parallel-self wasting their energy on anyways? Chicks, booze, drugs and parties? All the things you can't have...not for much longer...You'll find him, then it's this reality's turn to run it's own series of executables.