Notes:

killlua535 requested a story where machi mentors killua. here's my shot at it - enjoy! and let me know what you think! let's have it take place before my other story, called enhancer.

also can you tell that the cover image was this non-artist's meager attempt at artwork?


Monday.

"You're not getting it!" Machi said, frustrated.

"And I don't need to!" Killua protested as he bolted for the exit.

A thread of Nen wrapped itself around him and pulled him back.

"Look, Killua. Neither of us want to be here," Machi said. "Your brother's paying me to practice my Nen stitches in front of you, and you need the training, so I'm here for a week–but only a week–to train you."

"In that time, I want us to comply with Illumi's request and make the ordeal easier for the both of us." Machi said.

Killua did not want to be around a member of the troupe that once kidnapped him and Gon. It was the best option, though, as Illumi had agreed to call a temporary truce on the hunt for Killua and Alluka if Killua would agree to "spend a week training, developing his Transmutation abilities, and furthering himself as the future heir to the Zoldyck assasination business."

Getting stronger and spending a week without fear of being captured was too good an opportunity to turn down, which was how Killua ended up in a training arena in Meteor City, getting pelted with needles and strangled by thread. Alluka stayed nearby, ready to run off with Killua if things went wrong and the arrangement turned out to be a trap.

"Fine." Killua suppressed his childish urge to refuse authority, remembering the advantageous opportunity Illumi was offering.

"Then start by showing me your Nen." Machi instructed.

Killua generated a shroud of electric Ren over himself. He focused and directed it at Machi in an expression of Hatsu.

Machi easily blocked the attack by whipping out a single Nen thread, absorbing the electricity. "Yeah, that's not going to be enough."

"On the outside, you're independent of the Zoldyck Family." Machi said. "But your Nen technique doesn't reflect that."

"What does that even mean?" Killua was exasperated.

"Never mind that," Machi waved a hand. "Here's something more tangible to work on: I challenge you to break one of my Nen threads by the end of the week, before our training is over."

And so they trained.

Tuesday.

"We'll simulate a battle." Machi said.

"'Simulate,' because you think I'm too incompetent to actually fight you?" Killua asked.

"If something is so obvious yet so unpleasant to voice, simply don't ask." Machi said.

Killua held in his irritation.

"Without further ado, let's start." Machi materialized her Nen.

Killua spread his feet apart in a fighting stance.

Machi shot out three needles, trailed by Nen threads, directly at Killua.

Killua dodged, dodged, and dodged again, barely in time. The needles and thread, after missing their target, returned swiftly to Machi's hands and folded neatly out of sight.

Killua shot out his own Hatsu in three streams of electricity. They made contact with Machi, but she was covered in a thin, barely visible layer of coiled thread. Completely unharmed, Machi broke out of her thread cocoon and the pieces of broken thread dissipated the remaining electricity.

Frustration growing, Killua tried a different tactic. He ran towards Machi and grabbed onto her arm. He then increased his voltage and forced Machi's contact with his electric Nen.

Unimpressed, Machi used her other arm to grab onto Killua's free arm and directed the energy back at him by forming a route from one arm to the other using a bundle of metallic threads.

Literally and mentally shocked by his own Nen, Killua leapt backwards, a good distance away.

He swung out two deceptively heavy yo-yos and threw them at Machi, perhaps taking inspiration from her string-attached projectiles.

"Killua, this isn't even Nen anymore." Machi scolded as she cleanly caught each yo-yo and redirected their motion downwards, onto the arena floor.

Machi frowned as she observed the two craters and pieces of shattered hardwood produced from the impact. "I shouldn't have done that. I'm going to get fined."

They continued on, Killua sprinting and jumping around Machi, trying to get a hit in with his various tactics. Machi responded with, literally, faster-than-lightning reflexes and defended herself with ease.

It was when Killua used Godspeed, the newest ability that he'd used against Youpi during the Chimera Ant war, when Machi couldn't keep up.

Killua sped around Machi, moving too fast for Machi to respond to his shots of voltage.

It became a contest of endurance, as Machi fortified herself with non-conductive thread, waiting out Killua's attacks.

Killua recognized the futility of his superior speed if his electricity wasn't inflicting enough damage, and gradually abandoned the attempt.

Once Machi judged that Killua was worn out enough for the day, she called a stop on their training.

"Alright," She turned to Killua. "We're done for today. Get out of sight before the maintenance crew comes."

Machi walked out the arena doors.

Wednesday. Thursday. Friday.

These days only reinforced the fact that Killua's fighting paled in comparison to Machi's. The fights were repetitive and unmemorable, save for one especially colorful victory of Machi's.

It started off similar to Machi's other openings, with needles and thread launching an attack from multiple directions.

This time though, Machi's shots were deliberate, not the usual, sporadic jabs from any and every direction, but aimed so that Killua would slowly defend and evade towards a singular, menacing direction.

Several feet behind Killua was a work in progress, the beginnings of a real, silken and tough spider web. The base structure was a set of threads tied together in the center, extending outwards and stuck to needles embedded at various attachment points in the arena. At the same time as Machi bombarded Killua, she also worked on weaving spiraling circles around that structure, forming a webbed trap.

Killua bolted and dodged, knowingly stepping closer and closer to Machi's prepared web, but doing so with no other choice, given the dangerously sharp needles guiding him.

One last needle flew straight for his center, forcing him to take one final step backwards before the needle turned upwards and embedded into the ceiling. Killua stepped into an elaborately weaved web of thread, attached at multiple ends to the frame of the arena's doors.

"Did you have to make a spectacle of my defeat?" Killua complained, stuck and unable to escape.

"Get out of it by yourself." Machi said as she left Killua to his own devices, walking out of the arena.

Saturday.

Machi couldn't see why it was so hard for Killua, a Nen student with a one-in-a-million gift for the power, to make such simple progress.

Machi normally would not concern herself with mentoring, opting instead to spend any available time honing her own Nen. However, for Killua's training, Illumi was paying her, and when Machi was given a benefit, it didn't sit well with her to owe someone.

And when she did return a favor, she'd make sure to do it correctly. The best remaining option was for her to understand him more clearly, to see his background, urges, and inhibitions in order to help Killua move past his roadblock in Nen training.

"Killua, you've developed and strengthened your electric Nen, but at the end of the day, you're a Transmuter. Being a Transmuter means being able to freely change the quality of your Nen to anything you want." Machi said.

Machi continued, "Now here's an old, almost obsolete technique that I want us to try. The Transmutation Spectrum is a practice that Transmuters rarely use anymore because it has no use in combat. Although it's helpful when learning Nen, the practice takes a damn long time to carry out and a stroke of luck to pull off. I have a hunch, though, that it'll work for us today."

"It's something that Pakunoda showed me." She added quietly, as if for her own sake.

"But Pakunoda was a specialist…?" Killua said.

"Killua, the Nen types are more closely intertwined than you think. Think of them as the expression of an idea. There are many ways to convey your thoughts, but the core message remains the same. Pakunoda's powers were centered on memory, so she simply found alternative ways to express the idea of memory." Machi said.

"But that's besides the point. Tell me. What does your electricity feel like?" She asked.

Killua said, "It feels like white-hot, rapidly vibrating little particles–electrifying."

"Okay, now activate those feelings and then imagine your Nen becoming cold, solid, and somber." Machi said.

Killua materialized his electric Nen. He then felt the rapid, white-hot particles around him and willed them to settle down, to cool, and to freeze. Killua's electricity spluttered a few times before turning into little splinters and flakes of ice.

"Yeah, I know," Killua said. "I've tried ice before, but it's not as strong as my electricity."

Machi said, "I'm not looking for your Nen to be strong. I'm looking for it to be flexible and changeable. Next, imagine your nen becoming burning, gaseous, and angry."

Killua's ice did a one-eighty and morphed into small, ignited sparks. Not enough to be a full-on fire, but the beginning embers were there.

"Now imagine your Nen becoming hungry, biting, and dissolving anything in its way." Machi said.

Killua produced an acid that ate away at the floor he stood on, emptying a new crater in the once polished floor.

Machi cursed. "You know what? Have Illumi pay for all the damages."

Killua went through several more Nen qualities. Sticky, stretchy, and sweet for gum (was that how Hisoka felt most of the time?). Fuzzy, absorbent, and comfortable for cotton (who needed cotton Nen?). Fluorescent, blinding, and ephemeral for light (what was this, an interior design class?)

"Now, you're going to continue changing your Nen–however you want, whichever way your instincts lead you. Base the process on whatever fickle feeling arises, and whatever stray thought crosses your mind.

Machi started her own Transmutation Spectrum. She materialized water vapor, wind, and molten plastic.

Metal, wood, and honey from Killua.

Their Nen qualities changed rapidly and erratically, based on each moment's passing thoughts and whims: what made them angry, what made them hopeful, what made them concentrate, and what made them feel intense need.

Machi: cellulose.

Killua: quicksand.

Machi: mud.

Killua: cookie dough (he was exasperated).

Machi: magma.

Killua: poison.

Machi: water.

Killua: water.

Their Nen took on the quality of water, a common, nondescript element. But it was a defiant one, one that refused to take on a single shape. It changed freely depending on its container and evaporated into the air as soon as the chance arose, becoming completely free of gravity as well as the containers and limits in life.

Machi and Killua matched their Nen, apparently, purely by chance. As soon as they did, their Nen extended and integrated seamlessly with each other.

That was when a paranormal, out-of-body experience began for the two Transmuters.