Gosu - Chapter 136

I think the main reason he does that is pretty simple: his master told him to go kill the other four, but other than them he doesn’t want to kill anyone, he’s always tried to beat them without using any lethal moves. But now since the enemies have been getting stronger he’s had to use killing attacks to finish the fight, but he’s still holding back a lot, so he always waits until he’s in a bad spot to do it.