Library Of Ruina is Project Moon's 2021 deck battler, where you run a Library that mails out invitations, fights the Guests who accept, and turns the losers into Books. Every librarian is defined by one Key Page, which fixes HP, Stagger Resist, Speed and the Slash, Pierce and Blunt resistance columns, plus a deck of exactly 9 Combat Pages. Fights resolve as clashes: both sides roll dice at each other, the higher roll wins and the loser's die is destroyed, so damage is something you win rather than something you spend. Books drop the pages that build the next deck, which means the difficulty curve is assembled out of whatever you beat last.
This guide covers everything you need: core mechanics, the best builds, equipment worth investing in, location progression, and the tips that actually make a difference.
Core Mechanics
Clashes and speed dice
At the start of each scene every character rolls speed dice, and those results set both turn order and who can be targeted. When two characters point at each other their dice clash one pair at a time, higher roll wins, and the loser's die is destroyed without dealing damage. If nobody redirected onto you, the attack is one-sided and lands every die in full, which is why a scene where you win the speed roll and a scene where you lose it are two different fights.
Light and page cost
Light pays for Combat Pages. Characters start a Reception at maximum Light, recover 1 per scene, and get a full refill every time Emotion Level rises. Staggering or defeating a target hands back 1 Light, so a cost 1 page that finishes a wounded guest is effectively free. Cost 0 pages like Rules of the Backstreets exist precisely because the Light economy, not the hand size, is the real constraint.
Stagger Resist and damage types
Every hit reduces HP and Stagger Resist on separate tracks with separate resistance tables. Drop a character's Stagger Resist to zero and they discard all dice and pages for the following turn. Resistances run Ineffective 0.25x, Endured 0.5x, Normal 1x, Weak 1.5x and Fatal 2x, listed per damage type, so a guest can be Endured against Slash on HP while being Weak to the same Slash on stagger.
Emotion Level
Emotion starts at 0 in a Reception and climbs to a cap set by Floor level for librarians and chapter rank for guests, up to 5. Clashing gives 1 Emotion Point, rolling a die's maximum or minimum gives 1, defeating a target gives 3 positive points and losing an ally gives 3 negative ones. Each level adds 1 maximum Light and refills Light, level 4 grants an extra dice slot and level 5 improves the draw.
Books and Reception invitations
Beating a guest drops their Book, which you burn at the desk for Key Pages and Combat Pages. Books double as invitations, so you pick which guest arrives next instead of being pushed down a fixed track. That is the loop: the pages you strip off one reception are the pages you need to survive the one you deliberately schedule after it.
For a deeper dive into how these systems interact, see our Library Of Ruina combat guide.
Builds Overview
| Build | Tier | Playstyle | Key Stats |
|---|---|---|---|
| Floor of General Works | A | Versatile approach | Balanced stats |
| Floor of History | A | Versatile approach | Balanced stats |
| Floor of Technological Sciences | A | Versatile approach | Balanced stats |
| Floor of Literature | A | Versatile approach | Balanced stats |
| Floor of Art | A | Versatile approach | Balanced stats |
For full build breakdowns with gear and stat priorities, see our Library Of Ruina builds guide. For rankings, check the tier list.
Equipment Guide
| Equipment | Why It Matters | Best For |
|---|---|---|
| Slash dice | One of the three offensive damage types, and the one most Bleed pages are attached to. | Bleed decks, and any guest whose Key Page reads Weak at 1.5x or Fatal at 2x in the Slash column. |
| Pierce dice | The second offensive type, tracked on its own resistance row for both HP and stagger. | Guests who are Endured at 0.5x against Slash but Normal or worse against Pierce. |
| Blunt dice | The third offensive type. | Hands that stay full, and stagger-focused plans where the Blunt row is the weak one. |
| A Zwei Fixer's Page | An Urban Legend rank Key Page, sitting in the same tier as A Stray Dog's Page and the Grade 8 Fixer pages. | Mid-game floors that need a durable body while the good Combat Pages are still being printed. |
| A Grade 7 Fixer, Page 1 | One rung above the Grade 8 Fixer pages, on the City's fixer scale where Grade 9 is the bottom and Grade 1 the top. | Replacing default Assistant Librarian pages once Urban Legend receptions start dropping Books faster than you can burn them. |
Slash dice: One of the three offensive damage types, and the one most Bleed pages are attached to. Sharpened Blade at cost 2 rolls two Slash dice at 1 to 3 plus a Block die at 4 to 5, and raises Slash power by 2 for the scene on combat start.
Pierce dice: The second offensive type, tracked on its own resistance row for both HP and stagger. Pierce and Slash are mechanically identical rolls, so the entire decision is which column of the guest's Key Page is softer.
Blunt dice: The third offensive type. Will Make Fine Silk at cost 2 pairs a Block die at 4 to 6 with two Blunt dice, adds Fascinating Fabric to your hand, and gains 1 Power for every page held.
A Zwei Fixer's Page: An Urban Legend rank Key Page, sitting in the same tier as A Stray Dog's Page and the Grade 8 Fixer pages. Key Pages set HP, Stagger Resist, Speed, all three resistance columns and the passive slots, so this is the frame every deck is built on.
A Grade 7 Fixer, Page 1: One rung above the Grade 8 Fixer pages, on the City's fixer scale where Grade 9 is the bottom and Grade 1 the top. It arrives in the same Urban Legend batch, so upgrading a whole floor happens in one pass rather than one librarian at a time.
Full breakdowns in our Library Of Ruina weapons guide.
Location Progression
| Location | Level Range | Key Rewards |
|---|---|---|
| Canard | Chapter 1, one floor available | A Yun's Office Fixer Page 1, A Hook Office Fixer Page 1, first real Combat Pages |
| Urban Myth | Chapters 2 to 3, two or three floors | A Hook Office Fixer Page 2, A Backstreets Butcher pages, the four Lulu's Friend pages |
| Urban Legend | Mid campaign, four floors | A Zwei Fixer's Page, A Stray Dog's Page, Grade 8 and Grade 7 Fixer pages, Axe Gang Member pages |
| Urban Plague | Late campaign, six to eight floors | The Carnival's Page, Salvador's Page, Tamaki's Page, Will Make Fine Silk, Ink Over |
| Urban Nightmare | Endgame, all lower floors at high Realization | Star of the City access, Floor of Philosophy, Floor of Religion |
Canard: The opening rank, fought entirely from the Floor of General Works. Finishing episode 3 of Yun's Office opens the Floor of History, and clearing the Hook Office reception opens the Floor of Technological Sciences.
Urban Myth: The second rank, where guests start bringing passives worth reading. Episode 1 of Streetlight Office opens the Floor of Literature, giving you three floors to rotate receptions between.
Urban Legend: Reaching this rank unlocks the Floor of Art outright. This is the first tier where the Key Page pool jumps in quality, and where default Assistant Librarian pages stop being acceptable.
Urban Plague: Guests here punish sloppy resistance checks. Finishing the Shi Association reception opens the Floor of Language, and clearing the Puppets reception after that opens the Floor of Social Sciences.
Urban Nightmare: The rank before Star of the City, which is itself the gate on the Floor of Philosophy. Clearing a single Star of the City reception then opens the Floor of Religion, leaving Impuritas Civitatis as the last tier.
See our maps & locations guide for detailed area breakdowns and our walkthrough for the optimal progression path.
Tips That Actually Matter
- Open the guest's Key Page before you build. The Slash, Pierce and Blunt columns run Ineffective 0.25x, Endured 0.5x, Normal 1x, Weak 1.5x and Fatal 2x, and the stagger table is separate from the HP table, so a fight can be won on stagger with damage types that barely scratch health.
- Redirecting is free and it is the strongest button in the game. Pointing a librarian at whichever enemy die would otherwise hit unopposed converts a one-sided attack into a clash, and a clash you lose still destroys nothing except one die.
- Emotion Points come from clashing at all, not from winning. Losing a clash still pays 1 point, and rolling either the maximum or the minimum on a die pays another, so a scrappy scene often levels your whole floor faster than a clean one.
- Emotion Level 4 grants an extra dice slot and every level refills Light, so the fourth level is worth more than the first three combined. Plan the fight so the level up lands before the guest's own escalation, not after it.
- Defeating or staggering a target refunds 1 Light. Finishing a nearly dead guest with a cost 1 page is a net gain, which is why cheap closers earn deck slots over expensive ones that look stronger on paper.
- Decks are exactly 9 Combat Pages per librarian, and pages are drawn, not summoned on demand. Three copies of the page the build depends on is normally correct, because two copies in nine cards will not show up when the plan needs it.
- Bleed and Burn decay differently. Bleed loses a third rounded up each time an offensive die is used, while Burn ticks and loses a third at the end of the scene, so Bleed rewards attacking guests and Burn rewards defensive ones.
- Paralysis has a floor of 1, so it never removes a die outright. Use it on the guest's single biggest die rather than spreading it, because cutting a 10 to a 7 changes clash odds far more than trimming three small dice.
- Books are invitations, which means the order of the campaign is your choice. Farm one reception you already beat to print spare pages before scheduling the guest that keeps wiping the floor.
- Floor of Natural Sciences needs every lower floor at Realization Level 4, so ignoring Floor Realization for a stretch will lock you out of the mid-game roster even if your combat is fine.
Common Mistakes to Avoid
- Building a deck around damage types the guest resists at 0. 5x or 0.25x
- Letting enemy dice go unclashed because redirecting looked risky.
- Running one copy of the key Combat Page in a 9 card deck.
- Spending Light on cost 4 pages while a cost 1 finisher would have refunded it.
- Ignoring Floor Realization until the Floor of Natural Sciences requirement blocks progress.
Frequently Asked Questions
Do I need to play Lobotomy Corporation first?
No. Library Of Ruina shares its setting and its Sephirah characters with Lobotomy Corporation, and the nine named Floors are the same figures in new jobs, but the systems have nothing in common. Lobotomy Corporation is a facility management sim about work orders; this is a deck builder about clashing dice, Key Pages and Floors. Playing the first game adds story payoff, not mechanical knowledge.
How big is a deck?
Exactly 9 Combat Pages per librarian, plus one Key Page that supplies the stats and passives. A floor fields up to 5 librarians, the Patron Librarian and 4 Assistants, so a full reception loadout is 45 Combat Pages spread across five different roles.
What actually happens in a clash?
Speed dice set the order, then the two characters' dice meet one pair at a time. The higher roll wins, the loser's die is destroyed and deals nothing, and a winning offensive die applies its damage. If a die is never contested it becomes a one-sided attack and lands in full, which is where most losses come from.
Which Floor should I invest in first?
The Floor of General Works carries the opening chapters alone, so it gets your first good Key Pages by default. After that the Floor of History and the Floor of Technological Sciences unlock from Yun's Office episode 3 and the Hook Office reception, and spreading pages across three floors beats stacking everything on one.
How long is the game?
The rank ladder runs Canard, Urban Myth, Urban Legend, Urban Plague, Urban Nightmare, Star of the City and Impuritas Civitatis, with ten Floors unlocking along the way. Most players finish the story somewhere past 60 hours, and the final rank is where the deck building actually gets tested.
More Library Of Ruina Guides
- Library Of Ruina Best Builds
- Library Of Ruina Tier List
- Library Of Ruina Walkthrough
- Library Of Ruina Beginner's Guide
- Library Of Ruina Tips & Tricks
- Library Of Ruina Weapons Guide
- Library Of Ruina Combat Guide
- Library Of Ruina Boss Guide
- Library Of Ruina Maps & Locations
- Library Of Ruina Crafting Guide
- Library Of Ruina Classes & Characters
Similar Games
If you enjoy Library Of Ruina, check out these related guides:
- Slay the Spire Guide: card-game game with similar mechanics
- Balatro Guide: card-game game with similar mechanics
- Sultan's Game Guide: card-game game with similar mechanics
