Miki watch. Miki see Casa. Miki know Casa.

Casa enemy.

The First Precept of How to Get Your Boyfriend to Stop Talking to Other Girls:

Surveillance.

Casa climbed the stairs on the face of the 2-story pyramid. She stood in front of the book on the enshrined pedestal.

She reached out, paused, then grabbed the edge of the book.

She jumped backwards. No traps? None? Okay! She took the book with her and traipsed back down the pyramid.

Casa naive. Miki had already touched the book with her Index Magic. Wherever that book went, she would know where it was. As to how she figured out Casa would come here—call it a woman's intuition.

Casa left the pyramid chamber and found herself at a loss. Miki could've been anywhere by now. There weren't any immediate clues, but it was no use waiting for one to come her way. She picked a random corridor, hoping she'd pick up on her trail.

Miki went one step ahead of her, marker in hand. She drew an arrow on the wall, pointing down another corridor, continuing to do this until she arrived at a proper ambush site. Good place. Casa would find the arrows and think that they were Miki's attempts at not getting lost, and hopefully, she'd follow them straight into Miki's trap.

However, to simply wait and see was not enough. Casa could be unexpectedly dumb and deviate from the markings in a fit of cynicalism. There had to be some sort of external force to push her along the right way. She also needed to gauge and wear down Casa's strength to a level that she could handle.

To do so, she had to attack Casa.

The Second Precept:

Probing Attacks.

Miki stood in the intersection of several corridors, raring for violence. She had already set up her Relays all throughout this part of the labyrinth. All that was missing were the Bullets.

From the floor, walls, and ceiling, chunks of rock were gouged out and chiseled into ellipsoid bullets by magic, leaving the corridor around her looking like it's been bored out by a Magilian stoneworm.

Miki added each of the Stone Bullets to her Index.

Even if she was an Information Magic specialist, it's not as if she couldn't do something so basic as Bullet attack magics. Rather, it was because she had her Index Magic that even ordinary attack magics could become so devastating.

Relay connections okay. 500 Bullets ready. Have fun, Casa.

She had to be careful not to seriously injure Casa before she reached the ambush site. The point was to wear her down and guide her, after all.

Even if that was the intent, Casa felt the breeze of a murderous wind come from behind her.

Followed by a hail of Bullets.

By the way, the Evasion Aptitude Test was designed to increase Librarians' survival rates when faced with office drama such as this.

Casa ducked in time. Some of the Bullets ricocheted against the sides of the corridor, chipping away rock with tiny explosions borne of pure kinetic energy.

She pushed up on all fours and started to sprint. Turning the wrong corridor, there was another hail of Bullets waiting for her, forcing her to turn the other way.

Such a thing was possible through Miki's Relays. She could send magic instructions to each Relay, each one acting as a proxy for herself. They were her eyes, her ears, and her magical hands—all invisible and unseen to the enemy.

This wouldn't be possible without a way to track each Relay's position and state in realtime—something that she could easily do through her Index Magic.

Casa splendidly evaded the Bullets, but Miki was having too much fun. She barraged her hated friend with 50 Bullets all at once, leaving absolutely no room for evasive maneuvers.

Casa's evasion radar blared, leaving her no choice.

She had been feeling Miki's magic all along. The Relay lines permeated the corridors, lit up with Miki's beautiful blue hues in Casa's eyes—making it easy for her to directly tap into them.

Casa's specialty was to tamper with Akashic Chains, including that of the naturally-occuring, and most elusive, World Akasha. Compared to that, tampering with an artificial one was easy, and Miki's Index really was just an artificial Akashic Chain, albeit one that was part of her very being.

She stopped close to one of Miki's Relays and took a deep breath.

Relay Hijack.

Miki had been using two Relays to accelerate her bullets—one to push, and one to pull, essentially doubling the acceleration. At these ridiculous speeds, Casa had been having a hard time dodging.

So what would happen if the pulling Relay were flipped?

On top of hijacking and flipping the Relay's output, she added her own power. The sudden reversal and doubling of the magic vector decelerated the Bullets so fast that they crumbled against their own inertia, pulverizing them instantly. A curtain of stone dust exploded in front of Casa, the particles wrapping her figure as she ran through them with valor.

Realizing her Relay had been hacked, Miki quickly cut off the Relay from her network. It was now useless both to her and Casa.

In that moment, though, Casa figured it out. Having infiltrated Miki's Index, something that was almost a part of her being, she tasted her distortions.

Now she really needed to confront her.

The fight between Infomagicians continued.

It was not all attack magic, however.

The Third Precept:

Deception.

Before the Relay was cut, Casa easily traced the origin of the magic. She had been following a bunch of scrawled-on markings on the walls, but the origin of Miki's magic deviated from them, leading her to suspect that the markings were an attempted ploy to lure her to an ambush site.

On top of that, Miki was sure to cut off any Relays that she got close to, so she couldn't anymore rely on that vector reversal trick on defend herself against saturation attacks.

For now, she refrained from dodging. Dodging distracted her from formulating complicated magic. In the meantime, she fired her own Stone Bullets against the ones incoming from the front, while setting motion-detecting Bullet landmines in the steps she left behind.

The landmines were really just motion-triggered Bullet spells, and had little energy, but it was still enough to divert the trajectory of another Bullet.

Another saturation attack came.

Vector replot.

To accelerate a Stone Bullet to lethal velocities, there needed to be a straight-line distance of at least 20 meters. This was the Bullet's launch line.

However, what was a straight line? The standard Stone Bullet spell would need to ask the World Akasha what a straight line was. The World Akasha then gave the spell all the coordinates that made up that line—not just two points, but the infinity of points along the entire path.

What Casa redefined was not what a straight line was, but how the World Akasha responded to the question. It was basically a middleman attack.

In this way, she didn't need to be physically close to Miki's Relays. She only needed to be close to the launch lines, then she could make them spread out around her.

The bullets veered off course and ricocheted off the walls around her. The sound of 50-something Bullets at maximum velocity, bouncing off rock not 2 meters from her ears, was like the violence of a thick boulder being cracked with a god whip.

Regardless, she kept running.

She was almost there.

She emerged to a chamber.

This labyrinth was obsessed with chambers.

She looked and looked, but Miki wasn't there.

The passage collapsed behind her.

The Fourth Precept:

Entrapment.

"Casa… Not good enough."

"Miki?!"

Shards of ice shot at Casa from multiple directions. She did her best to dodge them all, and she did—but they weren't supposed to deliver the killing blow anyway.

She didn't see that Miki had walked up to her with an ice sword raised up high.

The Fifth and Last Precept:

Murder.

Indeed, your boyfriend wouldn't hit on other girls if they weren't left alive.

The sword swung down and dug into Casa's shoulder. She winced at the pain, but this was nothing.

Casa's ability to withstand pain—maybe her background was a little too deep?

She was brought to her knees. Miki had a smug face, but she did little more than to hold the handle of the sword that was still stuck in Casa's shoulder. There wasn't any sign of her making it dig deeper.

"I'm… sorry…" Casa pushed the words out of her mouth.

"Think sorry enough?"

"I… wanted… to be friends… with you too…"

Despite the trailing ellipses, she wasn't dying. It really just hurt a lot.

Her words were like a stab into Miki's heart.

"Friends…"

The First and Only Precept of How to Get Your Friend's Girlfriend to Stop Thinking You're Hitting on Said Friend!:

Understanding.

It was obvious to anyone that Miki's behavior had been irrational from the start.

Aloof and attached to Zanderfon and Zanderfon only, Casa initially suspected that she was simply just "one of those characters," but she wouldn't even listen in on their conversations. She would speak when spoken to, sure, but it had always felt detached.

The only thing that kept her in the group was Zanderfon's friendship with Larissa.

The level of her attachment to Zanderfon was, to such an extent, abnormal.

That this issue exploded was a matter of unlucky timing. The labyrinth reacted to one's deepest desires, and offered the quickest route to reaching them.

Quick didn't mean good.

—Don't butt into my life with Zanderfon.

That message was obvious.

—Don't make me lose the only thing I have left.

Maybe that's what she wanted?

"Were… you alone… for a long time?"

"Mm."

"Did… Zanderfon… save you?"

"Mm."

It was a messed up story. Casa didn't know the full picture, but one thing was clear.

Dependency.

Was Zanderfon also to blame? Maybe he also struggled to wean Miki off of himself, but such a thing would be difficult. The two, after all, were more than comfortable with each other.

"Miki… I wanted… you… to be part… of my life…"

Those words stirred something in Miki's mind.

—Be my friend.

All strength left her body. She let go of the sword. The ice returned to magic. She fell to her knees in front of a bleeding Casa.

"Ah… Ah!"

She quickly took out a bandage and pushed it onto Casa's wound.

"I… I… Oh no…"

Miki's face was twisting in panic and she was about to cry—I cut Casa! I did crimes!

But Casa just laughed.

Zanderfon burst into the scene.

"MIKI! IT'S NOT YOU, IT'S ME!"

This guy.