There's a God in Your Head?

Rumble—crash!

The sound of collapsing stone thundered behind us in rapid succession. We ran without so much as a glance back at the entrance, and before long the rockfall noise faded into the distance.

Looks like we were safe enough here. I stopped and looked back. Iris was leaning one hand against the wall, gasping for air.

"Hah… hah…"

"You all right?"

"Your stamina is… impressive. Whew…"

"Let's rest a bit before we go on."

Iris answered by sliding her back down against the wall. I took the opportunity to survey our surroundings. Faintly glowing moss clung to the rock faces — enough to make out the passage, but not enough to see each other's ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠faces clearly.

Iris raised a hand. A pale blue light bloomed from her palm, brightening the dark cave just a little.

"Leon."

She looked at me.

"…Why did you try to save me?"

"Huh? What do you mean?"

"When we fell off the stone path, you were the only one who grabbed my arm."

Her voice dropped lower.

"If you hadn't caught me, you could have stayed up there. So why…"

I don't get what she's asking.

What, was I supposed to just stand there and watch someone fall right in front of me? It's not like I made some grand decision and threw myself after her. My hand moved before I thought about it, and by the time I came to my senses, we were falling together.

"I didn't save you because it was you, Iris."

"…What?"

"I would've grabbed anyone who fell."

Though if they'd weighed, say, two hundred kilos, the story might've been a little different. Why would I grab that? My arm would come off.

"I just grabbed, and this is how it turned out. Nothing more, nothing less."

"…"

Iris's expression stiffened slightly. Maybe I phrased that wrong. Not that I could lie about it, either.

"I see."

She slowly lowered her gaze.

"I was mistaken, then."

"Yeah."

"To you, I wasn't even a rival. Just another ordinary mage."

"What are you talking about now?"

"Even so, I won't give up."

Iris looked at me again.

"Someday, I will earn your recognition."

"W-wait a second."

This conversation keeps veering off in completely different directions. I've been confused since yesterday — I think I need to ask properly this time. Does she hate me or something?

"Why do you keep trying to compete with me?"

"…"

"I'm a complete beginner who doesn't know anything. I've only been learning magic for three days. So why have you been like this since yesterday?"

"…Lying again."

"No, why won't you believe me? I'm serious."

Iris still looked unconvinced.

"Then why did you say all those empty compliments starting from the lower floors?"

"Empty compliments?"

"That I was capable, that it was comfortable having me around…"

"You asked me to say those things."

"When did I?"

"You said, 'Well? How was that?' every time."

Every time she took down a monster, she'd deliberately look my way to check my reaction, and if I didn't say anything, she'd demand my impressions first. She asked, and now she's complaining?

"So I told you what I actually thought, and you got mad."

"…Your tone was sarcastic…"

"I've been saying exactly what I meant from the start. You're the one who took it as sarcasm."

Iris stared at my face for a long moment. I had no reason to look away, so I stared right back. After a while, she pressed a hand to her forehead and let out a long breath.

"If you really are a beginner mage, then how do you explain the Continuous Trajectory Formula you used yesterday?"

"Huh? Explain what?"

Iris's eyebrow twitched.

"Your abnormal formula calculation speed."

"Formula… what?"

"The Mana Bullets you used at the training grounds. To pierce eight targets in succession with the Continuous Trajectory Formula, you have to continuously calculate coordinates, trajectory, internal mana rotation, and output loss."

Her voice dropped.

"More than fifty per second."

"…Fifty?"

Iris took a step closer.

"You calculated over fifty different formulas every second. An ordinary mage struggles to process more than five. Even most archmages can't handle twenty."

I blinked. What is she talking about?

"AI. What is she saying right now?"

I asked under my breath.

We were doing that?

I just asked ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠it to hit all the targets.

"…Why didn't you tell me?"

"Leon?"

Iris stepped closer, studying my face.

"Who were you talking to?"

"Ah, well…"

How do I explain this? Even if I went into detail, she clearly wouldn't understand.

Hmm… this world has to have something similar, right?

"…It's like a spirit."

"A spirit?"

"Could be a god, could be a demon. Doesn't really matter."

"A god…?"

"Anyway."

I tapped my temple with a finger.

"There's something in here that's ridiculously good at calculations. It did it for me."

Iris's eyes slowly widened.

"There's a… god in your head?"

"More or less. That's the idea."

I'd just said whatever to dodge a proper explanation. But Iris kept staring at my head without moving for a long time.

"Anyway, I've genuinely only been learning magic for three days. I don't even properly know what a formula is."

"…Show me your wrist."

"Out of nowhere?"

"I need to check something."

I held out my right arm. Iris wrapped her fingers around my wrist. Her touch was colder than I'd expected. A faint thread of mana seeped through my skin and into the tissue beneath.

It felt like a thin thread brushing along the inside of my arm. A little ticklish, even. Iris kept her eyes closed and didn't move for a while. The suspicion on her face gradually hardened into something else.

"…How is this possible?"

"What's wrong?"

She gripped my wrist a little tighter. The cold mana climbed past my elbow this time.

"Your Mana Circulation Path is barely refined at all."

"Explain."

"When you use magic for a long time, the pathways mana repeatedly flows through naturally widen. But yours…"

Her gaze stayed fixed on my wrist.

"Even the microscopic damage from the first time you ever channeled mana is still there."

"How long does that usually last?"

"About a week, normally…"

Her voice grew smaller and smaller.

"…Good heavens…"

"That's what I've been saying. Three days."

Iris slowly let go of my hand. She looked back and forth between my arm and my face as if she were examining an entirely different species. Looks like she finally believes me. Good that the misunderstanding got cleared up.

"You…"

Her gaze drifted to my temple. Her expression was a little strange. Confirming I was a magic beginner should have been enough for her to accept things, but she looked more confused than before. Well, maybe she just needed time to process it.

Clack.

Then it came.

Clack. Clack.

From deeper in the passage, something that sounded like bones rolling across stone. Iris immediately spun around and put herself in front of me.

"…Step back."

"What is it?"

"I don't know yet."

The blue light drifted slowly into the corridor. Something was walking toward us through the dim darkness.

Clack.

Yellowed, discolored bone. A tattered black robe. In one hand, what looked like a staff made of bone.

A skeleton in clothes? I heard the Tower has every kind of monster imaginable, but at least this one knows how to dress itself.

Iris raised her staff.

"…A Skeleton Mage. Not a strong one."

Blue mana gathered at the tip of her staff and instantly transformed into a spear of ice.

"Ice Lance."

Crack!

The ice spear shot across the passage. Before the skeleton could even lift its staff, the lance punched clean through the center of its skull. The cranium shattered into pieces, and the black robe crumpled to the floor.

"That was fast."

"This much is—"

"Hahahaha."

Iris's words cut off. The jawbone of ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠the fallen skeleton was clacking and moving. More than half its head was gone, yet the laughter came through perfectly clear.

"How long has it been since I've seen humans?"

The skeleton planted its staff and slowly pushed itself upright. The bone fragments scattered across the floor rose into the air, latching one by one onto the broken skull. Within seconds, it had restored its original form.

"Looks like you fell from above."

Two violet flames kindled inside ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠the robe's hood — where eyes should have been. The skeleton looked us up and down at a leisurely pace, then clacked its jawbone.

"Today is my lucky day. I was just in need of a usable head."

The color drained from Iris's face.

"That's…!"

"Oh. So that Skeleton Mage thing can talk?"

"…Get behind me."

Iris gripped her staff with both hands. Her expression was nothing like before.

"That is no ordinary skeleton."

"Then what is it?"

"…A Lich."

Her voice trembled low.

"That's a Lich."