I was running through my reading history, and came upon Bullet Train by Kotaro Isaka, which does involve multiple POVs from the killers. I misremembered a few details, like that it was the killer's handler mentioning the Pusher.
There are a lot of candidates to choose from, after all. Like the Pusher. You’ve heard about him, right? The one who pushes his victims in front of cars or trains and makes their deaths look like an accident. Some people say he’s the best in the biz.
A few chapters later, we do get a POV story from the Pusher, who's remembering someone speculating that he didn't exist.
Someone suddenly gets a cut on their arm or their leg, said the woman, and they scream, a kamaitachi got me! But really it was just a sharp wind. I think the Pusher must be the same sort of thing. Someone gets hit by a car or jumps in front of a train and people say it was the Pusher that did it. Couldn’t it just be a made-up story?
And indeed, he pushes a man.
Cars come from the right. Black minivan, female driver, short hair, child seat in the back. The timing’s off. The next car is coincidentally the same type of minivan. The light changes. The car surges forward. Asagao casually moves his hand, touches the man’s back.
There is the sound of impact, then the screech of the tyres clawing at the road. No one screams yet. The people’s shock is like a silent, transparent explosion.
Asagao is already gone. He walks fluidly back the way he came, like floating on a current. Behind him he hears cries of Ambulance! but his heart is calm, like the surface of a lake where no pebble has been cast. His only thought is the vague recollection that he had once done a job at this same intersection, a long time ago.
That last line might be a reference to Three Assassins by the same author.
Suzuki is just an ordinary man until his wife is murdered. When he discovers the criminal gang responsible he leaves behind his life as a maths teacher and joins them, looking for a chance to take his revenge. What he doesn't realise is that he's about to get drawn into a web of unusual professional assassins, each with their own agenda.
The Whale convinces his victims to take their own lives using just his words.
The Cicada is a talkative and deadly knife expert.
The elusive Pusher dispatches his targets in deadly traffic accidents.
Suzuki must take each of them on, in order to try to find justice and keep his innocence in a world of killers.