Yakumaru Itsuki

Yakumaru (薬丸 (やくまる)), known as Ya-kun (ヤっくん) to her comrades is a character introduced in Toaru Kagaku no Accelerator. She is a member of Scavenger.

Appearance
Yakumaru wears a loose square neck blouse and black spats. She wears a utility belt, likely where she keeps her vials of chemicals. She also wears a large brown newsboy cap, which she keeps her long hair in, as well as to hide her attractive looks.

Personality
Though a little more serious than Naru, Yakumaru still shares the same childish aspect as her comrades. Like all members of Scavenger, she does her job of killing people and destroying things without remorse or guilt, willing to eliminate those who get in the way. Moreover, she also hates teachers and believes them to be the source of evil in Academy City.

According to her, she has been teammates with Leader for a long time, making her perceptive enough to know what Leader was planning after coming into contact with Misaka Mikoto, who defeated Seike earlier without being told.

Toaru Kagaku no Accelerator
When Nakimoto Rizou realizes that DA has become a liability he contacts Scavenger's liaison to have them eliminate the group. The liaison wakes them up and announces to them via an intercom that they have a job to do.

They are later seen again razing the entirety of DA's headquarters in sector 3's warehouse district, apparently killing many people in the process. It is Yakumaru that tells them that they should make sure to finish their job as they would not be paid if they do not do so. Seike tells her that the place they destroyed wasn't the only targets and notes a mysterious bodybag with a girl inside it that DA took with them. They later track the surviving DA down using the Predator ability.

Later showing their disregard for their targets and people who get in their way, they destroy a small contingent of Anti-Skill they meet along their way. Naru later taunts the Anti-Skill that tried to contact them and later unanimously agree to finish their job as quickly as possible. They arrive in great force with Naru using her ability on paper explains as bombs against both DA (and their Tarantula mobile weapon) and the Anti-Skill that were fighting near a tunnel. Yakumaru spends much of her time observing the battle. She is later saved by Seike when Hitokawa Hasami arrives with Estelle Rosenthal attacks them, much to her chagrin.

In the battle between Naru against Hasami, Estelle, and Yomikawa Aiho, she charges Yakumaru to take care of a surviving DA member, the driver of the Tarantula. She later kills the man with her coolant but the body is destroyed by Naru and she is later lectured by the other members for not properly killing him.

After Accelerator arrives, Yakumaru prepares a liquid thermite reaction in one of her spheres as part of Scavenger's combination attack. Like her teammates, she's terrified when Accelerator survives their attack and even more when they realize he's the #1 Level 5. Yakumaru is the third Scavenger member to be taken out by Accelerator, who defeated her by flicking her forehead while she was trying to put some distance between them as she mixed her chemicals.

Dream Ranker Arc
Yakumaru participates in Scavenger's operation to track down the robotic doppelganger of Kuriba Ryouko, in order to improve Scavenger's situation after their previous failure. They stop to use a public bathroom, and Naru teases Yakumaru over how long she took. After locating the doppelganger, they proceed to the Shinasame University DNA Map Analysis Laboratory, only to find the doppelganger gone. Yakumaru blames this on Naru wanting a popsicle, though she points out that they all got one too. However, Leader is confident that it won't escape her eye. They catch up with the doppelganger after she confronted the original Ryouko. After capturing the doppelganger, Leader sends Seike after the original Ryouko to verify that they hadn't switched places, then taunts the doppelganger over her appearance and possible desire to be a real human. In response, the doppelganger partially breaks free and grabs Leader's arm, snapping it. Fortunately, Leader is spared from having her eye plucked out when Naru attacks the doppelganger.

Afterwards, Yakumaru notes that she would have intervened if Naru hadn't, and prepares to make a painkiller for Leader. However, the doppelgänger gets back up and demonstrates a new ability to control other materials, allowing her to incapacitate Naru. Unable to carry both of her allies away, she runs away and lures the doppelgänger into a trap. However, she ends up attacking a clone made of paper and is about to be crushed by the doppelgänger, but Naru wakes up and temporarily stops her. Yakumaru throws an explosive to slow down the doppelgänger and flees with her allies.

They regroup some distance away. Yakumaru gives her shirt to Naru (who was naked since the doppelgänger stole her paper armour) and asks Leader what they should do now. Leader says that they need to find Seike, but at that moment Misaka Mikoto approaches and tells them that she defeated Seike. Leader attempts to persuade Mikoto into working with them, and Yakumaru understands her plan and goes along with it. Naru nearly gives away the truth, so Yakumaru gags her.

Yakumaru and Naru are ordered by Leader to collect the unconscious Seike. Naru worries over leaving Leader alone with Mikoto, but Yakumaru thinks that she'd be more worried if Naru was still there.

Later on, Leader orders them to evacuate the Skill Outs from an area where they are planning to redirect the doppelgänger. They complain but follow the order. Yakumaru convinces the Skill Outs to leave by pretending to be a helpless girl and claiming that there's a poison gas leak. After the evacuation is complete, they join up with the rest of Scavenger and meet with their client in a warehouse. The doppelgänger breaks in (brought here by Leader's plan) and Leader uses the threat of her to coerce the client into signing off on their job. Yakumaru and the group then flee the scene.

Abilities
Yakumaru is an esper that can separate liquids by manipulating their specific gravity. Through this she can produce various phenomena by mixing the separated liquids. This is shown in battle, where she uses various types of chemicals she carries in her utility belt. One of the chemicals she uses is a special coolant to quickly freeze an enemy, killing them when their heart and brain freezes over. This coolant is of her own make, improved from the one that Academy City uses. Yakumaru can also make a liquid thermite reaction by mixing up her chemicals in one of the baseball-like spheres she carries in her belt. These spheres can be thrown at the enemy like a projectile, and the heat of the reaction reaches 4000 degrees. Other chemicals include a foam that expands to trap an enemy, a painkiller, a freezing agent, an explosive, and fuel for the special vehicles used by Scavenger.

She is also a skilled actress. By dirtying her clothes and wobbling as if injured, she can give off the appearance of vulnerability and convince others to do as she wants. For example, she is able to convince a group of Skill Outs to not only evacuate from their hideout but also to tell others to do so, by lying about a poison gas leak from a nearby factory.

Quotes

 * (To her comrades, from Accelerator Manga Chapter 7): "This is a business. As the Scavengers, we were hired to eliminate the organization as DA. If we let the target escape, not only do we not get our money, but we're charged for breach of contract."