Obviously, the plan to go had to be: close the distance while avoiding his attack, as step one, and as step two, kick the shit out of that asshole.
I proceeded with that plan, relying on my flying speed and the shadow walking, to dodge the hammer mainly. Why? Because I wasn't completely sure the dot was actually the ghost, and I didn't want to go all the way back somewhere else if I was wrong.
I may have wasted a couple of seconds in this way since I confirmed my first assessment very soon, but I'm still gonna protect my laziness in this approach. Knowing the target was actually the target, I decided to accelerate, and instead of flying started running up makeshift stairs created from the void essence.
I reached him fast, but he actually didn't seem to even plan to keep me at a distance. The hammer was still annoyingly trying to blast me away from behind, but that was all. When I actually tried to kill him, I found out why.
