The dagger flew at high speed. The mercenary have seen Leo use this skill before, so he knew how dangerous it was, so he dodged immediately.
Tried to dodge...
There is no way his reflexes and speed was faster than a dagger also threw with all his monstrous strength.
Even if he dodged, the dagger is sentient and could chase after him if Leo wills it.
So, before he could move out of the danger zone, the dagger had reached him and it blasted the mecenary by the chest, leaving a bloody hole right at that place.
Meanwhile, Leo could only pray that he killed the right person, because if not that person would activate his gift... And that would not be too good for him.
Sure enough, it remained two mercenaries. Since the one he killed wasn't 'one', then it means that out of the two is the person that is one.
And Leo knew who the person was.
Before he could act again, the man place his hands on his hand and then...
Nothing?