Kaito woke up to someone kicking his bed.
"UP! GET UP! Your tower opens in six hours and you haven't done ANYTHING!"
He cracked one eye open. The demon lord was looming over him, arms crossed, looking like a very irritated parent whose kid hadn't done their homework.
"Five more minutes," Kaito mumbled, rolling over.
"I will literally set this bed on fire."
"That's fair." Kaito sat up, rubbing his eyes. He'd gotten through eight chapters before falling asleep, which wasn't bad considering the circumstances. The book sat on his nightstand—which apparently existed now, along with a wardrobe and a bathroom that definitely hadn't been there yesterday. The tower seemed to adjust to basic needs automatically. Convenient.
The demon lord grabbed him by the collar and hauled him to his feet. For a entity made of pure demonic energy, it had a surprisingly firm grip.
"Listen here, you walking disappointment," it growled. "I don't care if you want to be here or not. The Tower system is ACTIVE. Adventurers are already gathering at the base. If you don't set up your floors, the system will generate a default dungeon, and let me tell you—default dungeons are BORING. No personality. No style. Just generic goblin caves and spike traps."
Kaito blinked. "So?"
"SO?! SO?!" The demon lord looked like it might actually have an aneurysm. "Do you want some random algorithm designing YOUR tower? You'll be stuck with whatever it makes for ETERNITY!"
That... was actually a good point. If he had to be trapped here, he might as well make it tolerable for himself. Generic goblin caves sounded depressing.
"Fine," Kaito sighed. "Where's the tower designer thing?"
The demon lord's expression shifted from rage to surprise to something almost like respect. "Top floor. I'll show you."
The throne room had a lot more doors than Kaito remembered. The demon lord led him through a corridor that seemed to stretch longer than should be physically possible, up a spiral staircase that made his legs burn, and finally through a golden archway into a massive circular chamber.
The room was empty except for a single pedestal in the center, on which sat what looked like a tablet made of crystallized light.
"The Tower Maker," the demon lord announced with dramatic flair. "With this, you can design every floor, every monster, every trap, every reward. You have complete control over floors one through ninety-nine. The hundredth floor is your personal chamber—that's auto-generated based on your... preferences."
Kaito picked up the tablet. It hummed with energy, warm against his palms. The screen lit up, displaying a wireframe model of a tower with 100 floors stacked vertically.
"You have five hours and forty-two minutes until opening," the demon lord said. "I suggest you start with floor one and work your way up. Most Dungeon Masters spend weeks planning their towers, but you don't have that luxury because SOMEONE spent sixteen hours sleeping—"
"Can you leave?" Kaito asked, already scrolling through the interface. "You're distracting."
The demon lord made a strangled noise, then vanished in a puff of sulfurous smoke.
Finally. Some peace.
Kaito sat down cross-legged on the floor and started exploring the menus.
TOWER MAKER INTERFACEDungeon Master: Kaito Yamada Tower Name: [UNNAMED] Floors Configured: 0/99 Time Until Opening: 5:41:33
The interface was surprisingly intuitive—kind of like a video game map editor, but with more existential dread. He could set themes, spawn monsters, place traps, design boss encounters, even write lore text that adventurers would find on scrolls or through NPC dialogue.
First things first: the name.
Kaito thought for a moment, then typed: Tower of Unnecessary Knowledge
There. That felt appropriately annoying.
Now, floor one. The template offered several biome options: Cave System, Volcanic Wasteland, Frozen Tundra, Dark Forest...
He selected Dark Forest. If he was going to be stuck here, he wanted something that at least looked nice. Forests were calming.
The wireframe of floor one filled in with trees, undergrowth, and a winding path. The system prompted him to select monsters.
Kaito scrolled through the options. Goblins—classic, abundant, annoying. He placed about fifty of them scattered throughout the forest. Then he added forest spirits, some wolves, a few giant spiders for variety.
But that was too straightforward. Too... normal.
He tapped the "Custom Parameters" button.
A new menu opened up with sliders and text boxes for adding special conditions. Kaito's eyes lit up—not with enthusiasm, but with the recognition of an opportunity for maximum irritation.
CUSTOM PARAMETERS - FLOOR 1
He started typing.
Environmental Condition: Random gravity shifts every 10 minutes. Sometimes normal, sometimes low gravity (jump too hard and hit the canopy), sometimes heavy gravity (moving becomes exhausting).
Monster Behavior Modification: All goblins have been equipped with kazoos. They play them constantly. Cannot be silenced, even in death. Sound carries through entire floor.
Navigation Interference: Path markers exist but randomly rotate 90 degrees every 15 minutes. Compasses spin uselessly. Maps auto-update with incorrect information.
Required Objective: Before proceeding to floor 2, adventurers must collect 10 "Knowledge Fragments" scattered throughout the forest. Knowledge Fragments appear as glowing books. When touched, they ask a random trivia question. Answer correctly to collect. Answer incorrectly, and the book teleports to a new random location.
Kaito leaned back, satisfied. It wasn't deadly—not yet—but it would be absolutely insufferable. Exactly the vibe he was going for.
He saved the configuration and expanded it to floors 2-10, adjusting the difficulty slightly for each level. More monsters, harder trivia questions, longer gravity shift intervals, additional kazoo instruments (floor 7 got tambourines).
Now for the boss of floor 10.
This needed a story. Adventurers loved stories, right? He'd read enough light novels to know the formula.
Kaito opened the Boss Design interface and started crafting.
FLOOR 10 BOSS: The Forsaken Saint
Lore Text (appears in journal entries scattered through floors 1-10):
"The town of Ashbrook was once blessed by the presence of Elara, a young healer whose kindness knew no bounds. But kindness, the Church said, was not enough. To serve the Divine, one must also enforce its will.
They asked her to condemn the sick who could not pay. To turn away the dying who questioned doctrine. To punish the faithful who wavered.
She refused.
So they made her into a lesson. Through forbidden rituals, they twisted her body and soul, transforming her into the very monster she'd spent her life healing others from becoming. Then they cast her into the forest, telling the people that THIS was what happened to those who defied the Church's wisdom.
Ashbrook still stands, just beyond the forest's edge. Its people still pray. Its Church still rules.
And Elara still screams."
Boss Design:
Appearance: A towering, corrupted figure wreathed in dark vines and broken halos. Her face is split—one half still human and weeping, the other half a twisted mass of bark and thorns. Chains hang from her wrists, inscribed with holy scripture.
Phase 1: Elara attacks reluctantly, apologizing between strikes. Her movements are slow, telegraphed. She can be damaged normally.
Phase 2 (50% HP): The corruption takes over fully. She becomes aggressive, fast, relentless. Adds spawn—manifestations of the Church's "lessons," small twisted angel-like creatures that divebomb adventurers.
Victory Condition: Defeat Elara. She dissolves into light, leaving behind a locket containing a picture of Ashbrook before the corruption.
Post-Boss Event: A path opens leading to a replica of Ashbrook. The town is populated by NPCs who treat adventurers as heroes, begging them to "save us from the monsters in the forest." The Church stands at the town center, its priests smiling benevolently.
Secret Objective: Adventurers can choose to confront the Church. If they do, the priests reveal themselves as the true monsters—mid-level bosses that drop better loot but make the next ten floors significantly harder as "divine retribution."
Standard Objective: Thank the priests, accept their blessing, move to floor 11.
Kaito read over his work. It was... darker than he'd intended. But also kind of interesting? He'd basically just written the outline for a tragic side quest.
Whatever. If adventurers wanted a generic power fantasy, they could go to a different tower.
He saved the boss design and checked the time.
Two hours left.
He'd done floors 1-10. That was enough for day one, right? The demon lord said most Dungeon Masters spent weeks planning. He'd done it in three hours. Overachiever.
Now for the important part.
He navigated to Floor 100 - Personal Chamber.
The screen displayed a message:
PERSONAL CHAMBER CUSTOMIZATIONAvailable Budget: UNLIMITED Restrictions: None (you're the boss, literally)
Kaito's fingers flew across the tablet.
Room Size: Massive. Like, aircraft hangar massive.
Walls: Floor-to-ceiling bookshelves on every surface except one wall, which would be a window overlooking... he selected "Peaceful Mountain Sunset (Eternal)."
Furniture:
One extremely comfortable bed (king-sized, memory foam, excessive pillows) Multiple reading nooks with bean bags and those egg-shaped hanging chairs A kotatsu for winter reading vibes even though weather doesn't exist here One gaming setup with a curved monitor the size of a small car A complete kitchen (he selected "Auto-Stocking: Japanese, Italian, and Thai cuisine")
Entertainment:
Giant TV (85-inch, 8K, connected to every streaming service that existed before the apocalypse) Spotify premium (infinite skips, no ads, even though there's no internet here—magic tower logic) Gaming console with every game ever made A tablet that could access any book ever written
Misc:
Soundproofing (very important) Temperature control (always perfect) A coffee maker that produces the exact right temperature and strength every time Ambient lighting that adjusts based on mood A door that locks and cannot be opened by demon lords without permission
He hit CONFIRM.
The tower shuddered. Somewhere far below, he heard the demon lord shout "WHAT ARE YOU DOING UP THERE?!"
Kaito smiled. First time since the apocalypse.
A notification popped up:
FLOOR 100 CHAMBER COMPLETEFLOORS 1-10 ACTIVEFLOORS 11-99: UNCONFIGURED (Default generation available)TIME UNTIL OPENING: 0:47:12
Good enough.
He set the tablet down and walked to the edge of the platform. A spiral staircase had appeared, leading down. Time to check out his new living space.
Floor 100 was perfect.
Kaito stepped into his chamber and actually felt something close to contentment. The bookshelves stretched endlessly, already filled with every book he'd ever wanted to read plus thousands more. The window showed a mountain range painted in eternal sunset colors—oranges and purples and golds that never faded.
The kitchen gleamed with unused appliances. The TV loomed like a shrine to entertainment. The bed looked so comfortable it was probably illegal.
On the coffee table sat a single book he didn't remember requesting: The Dungeon Master's Guide to Bliss
Kaito picked it up and flipped it open.
Congratulations, Dungeon Master! You've taken your first steps into tower management. This guide will help you navigate the complex world of adventurer psychology, optimal trap placement, monster behavioral patterns, and most importantly—how to make your eternal imprisonment as comfortable as possible.
Chapter 1: Understanding Your RoleChapter 2: The Care and Feeding of AdventurersChapter 3: Advanced Trap TheoryChapter 4: Monster Morale (Yes, It Matters)Chapter 5: Negotiating with Demon LordsChapter 6: Self-Care for Immortal Dungeon Masters
It was basically an instruction manual. A very thick instruction manual.
Kaito carried it to the hanging egg chair, settled in with a blanket that had materialized from nowhere, and started reading.
Outside his window, the sunset continued forever.
Somewhere ninety-nine floors below, adventurers were gathering at the tower's entrance, weapons drawn, ready to conquer the newest dungeon.
They had no idea what they were in for.
Neither did Kaito, really.
But at least he had a comfortable chair and a good book.
For now, that was enough.