I’m a sick bastard, so of course one of the first drawings I post of Justice is ANGST ANGST ANGST. With my version of the souls, you can interact with them and follow the three paths of neutral, pacifist and genocide. This is one of the many scenarios that would happen on genocide. In many ways fighting Justice is like fighting Undyne, similar goals and similar strengths. He would definitely throw himself in the way of Kindness, he values his friends and group members more then he cares about actually surviving.
For context of just how fucked this image is, during Justin’s time underground he used one of his bullets to shoot Undyne in the eye which is why she has a eyepatch when she fights Frisk. In the fight, he himself gets his eye taken out and the fight only goes downhill from there because without both eyes you don’t have good depth perception. Which is pretty important for SHOOTING WITH A GUN.