Miri Sugo/History

Control Devil arc
At an unknown point in time, Miri was brainwashed by Makima to serve her needs. He is summoned as part of Makima's newly-formed Special Division 5, a team of weapon hybrids created for the sole purpose of battling the fully-powered Chainsaw Devil. While under Makima's control, Miri tells the others that he wants to impress Makima on the group's first operation.

Once Makima commands Special Division 5 to attack, each member activates their weapon trigger, transforming into their Hybrid forms. They all leap from their respective spots to lunge straight towards Chainsaw Man. Before any of the Hybrids can land a single blow on him, they are blown back by Chainsaw Man leaping forward as he slices through Quanxi and Miri using one of his chainsaw legs.

The three crash through several skyscrapers before landing in an apartment complex. As he gets up, Chainsaw Man kneels over Quanxi and Miri's tattered bodies, clutching each of their severed heads before fighting the other Hybrids.

At some point in the future, Special Division 5's Hybrids are revived once more by Makima, who brings them all to a graveyard to confront Denji. Once Makima finishes monologuing her thoughts of erasing anything she dislikes to Pochita (who is disguised as Denji), Miri and the other Weapon Humans transform into their Hybrid forms for the final battle. Pochita starts by slamming his fists into the ground, lifting up a huge chunk of the ground to throw straight towards Makima using his chains.

Katana Man and Miri act first by leaping forward, both slicing the chunk of land and cutting it down into several dozen smaller chunks. However, the two are left vulnerable as Pochita falls towards them from behind the debris. Before the two Hybrids can act any further, Pochita swiftly uses his chainsaws to cut them both, defeating them in the process.

Current Arc
Several months after being freed from Makima's control, Miri joins the Chainsaw Man Church alongside Barem, the Whip Hybrid, and the Spear Hybrid. Together, they form most of the church's top brass. At some point, Miri is sent to recruit Denji as a potential member of the church. He eventually finds Denji in an alley sulking after the latter’s disastrous "date" with Fumiko Mifune.

Deciding to approach Denji, Miri stares at a recruitment poster for the Chainsaw Man Church, expressing annoyance over the inclusion of some nobody next to Chainsaw Man. Denji asks Miri why he's talking to him, to which he reveals that although they don't remember each other, the two have met before. Upon being questioned about who he is, the young man unhoods himself to Denji, introducing himself as "Sword Man".

Miri then goes on to attempt to jog Denji’s memory by explaining how they know each other. Denji is immediately dismissive of this and chooses to head back to school. Later, Miri is introduced to Denji's class as a new transfer student from Kanagawa. During his introduction, Miri shows a rather rude, abrasive side towards other students, even mentioning he has no intention of making friends. However, three girls immediately swarm him afterwards, causing him to irritatedly ask Denji to help get rid of them.

He later meets up with Denji and Fumiko on the school's rooftop to give the latter a message. Miri reveals the Weapons have high-ranking positions within the church and requests Denji to join them. Denji hesitates to accept the invitation, having resigned to his so-called "normal life". Despite Miri's best efforts and attempts at sympathizing with his past, Denji initially rejects the offer, much to his frustration. Miri tells Denji that he genuinely wanted to be his friend and that he could've slept with all the women he wanted if he had joined him. Reconsidering his choice, Denji tells Miri he now wants to join the church.

Miri takes Denji to the Chainsaw Man Church, and the two are guided through the building by Nobana Higashiyama. Denji becomes dumbfounded by unsettling nature of the place, especially with the crazy conspiracy theories and forced child marriages. He then yells at Miri for believing in the church's insane theories, stating that the church isn't what he was promised either. The two Hybrids begin arguing, only for Barem to arrive and cut off the argument. Miri observes Barem getting on Denji's nerves by threatening to ruin his life, as well as promptly suggesting to kill Asa to bring Chainsaw Man back. Upon hearing this, Denji bails out immediately while calling Miri and the other church members insane as he leaves the building.

The following day, the four members of the Chainsaw Man Church's Weapon Humans eat lunch at a Family Burger Restaurant. Barem reveals his plan for the Weapons to enact a murderous rampage throughout the city to force Denji back into the spotlight as Chainsaw Man. Miri appears conflicted over this idea, wondering if going along with the plan is really worth it. The Whip Hybrid advises Miri to discard any other lingering thoughts, to which Miri objects that he is a human being who can think for himself.

On the day of their planned massacre, Miri and his other two fellow Weapons arrive at a local food court in East Ogikubo under Barem's orders. The Spear and Whip Hybrids both express delight over harming innocent lives, while Miri expresses discomfort over Barem's insane plan. The Weapons then prepare to transform, only for Quanxi to intervene by cutting down the Whip and Spear Hybrids. Before Miri can retaliate in his transformed state, Quanxi swiftly slices him into pieces.