Trajectory Manipulation is the ability for the user can control a projectile's trajectory path once it is fired or thrown, whether it be a bullet, laser beam, boomerang, etc.
The user is able to control the path of an object flying towards them or another target. This allows the projectile to curve around barriers and obstacles to reach targets, attack at unsuspecting angles and blind-spots, confuse opponents as it keeps moving around before making the unexpected strike, and have it gain momentum and piercing power by flying around.
Diego has the ability to curve or even stop the trajectory of anything he throws, usually one or both of his dual knives, as well as other things in motion such as Soviet or Commission bullets. In the second season, he shows that he is able to manipulate the trajectory of bullets that are being shot at him.