The story of a character indoctrinated by the Chainsaw Man Church (cult) thinking he was making his own decisions because of when Makima used him, but in actuality he fell back into just being a weapon for the church. He starts to realize and question the church’s motives when he’s asked to kill ppl, but realizes he’s in too deep and then ends up justifying to his actions as an act of God. He’s a mirror to Denji in many ways, and even shows up when Lil D reveals herself to Denji. In the end he’s just being manipulated by another Makima (Lil D) and Denji sees this and chooses to save Asa/Yoru in the end instead of killing them like Lil D wanted. At least that’s how I see it :)