DNF70 epic pistol, a pistol with wings for sacrifice, is said to be the fall of a specific NPC in the abyss. Who can tell us which NPC fell and how to hit it with a high falling rate?

This epic equipment does not specify which NPC falls (such as the bright light knife, which is the designated NPC), but only brushes the corresponding abyss map. I always choose the hell level to brush the abyss, and I feel that the probability of ss is higher (but some people say that it is the same as brushing the king level abyss). I'm used to saving the highest rank or captain of the abyss for the last kill. If not, I will kill them at will.