#Borderkeep of the Spirit Realm (靈界邊境の關門)

Contents

Open-world sandbox campaign (10~20+ sessions). B2 "Keep on the Borderlands" × Konsei Reiyotan. Base(fortress) + wilderness(mountains) + dungeon(7 lairs). PC 1st~5th dan.

• Recommended Party: PC 3~4 people (1st~5th dan, with advancement during play)
• Difficulty: Variable (risk 1~4 by lair)
• Rules Covered: base life/job board/wilderness encounters/parallel exploration of 7 lairs/resource management between sessions

---

#Background

Sekimori border. A region where the gate to the Spirit Realm opens unstably. A great sealing rite 30 years ago barely suppressed it, but recently the cracks have begun widening again.

Kagura Domain built the border fortress Aofu(青府) to defend the region. PCs are Aofu garrison troops or independent adventurers.

There are 7 lairs in the mountains around the fortress. Each lair has become a base for a yoma faction. They are connected to one another — if one collapses, another changes.

---

#Scent

#Sensation of the First Scene

Aofu Fortress at dawn. Thin frost sits on the stone walls, and soldiers doze in the watchtower with spears upright. In the inner yard of the fortress, fallen leaves from last night have been pushed to one side by the wind.

Outside the south gate, mountains burn with autumn leaves. Beyond them is always a thin mist. That mist is not ordinary fog. It is the breath of the Spirit Realm leaking out. Experienced patrolmen guess today's danger by the density of the mist.

Three smells overlap in the air. The smell of horses from the stable, miso soup from the kitchen, and — from talismans carved beneath the pillars by Monk Myoan, a faint scent of fragrant wood. On days when this scent thins, the great seal is weakening.

There are three sheets of paper in front of the job board. Each brush hand is different. Someone wrote in haste, and someone wrote with trembling hands. Every morning in the fortress, someone posts these papers, and someone else takes them down.

#Voices of Key NPCs

Seki Masatora, Border Warden — low, curt speech. Shows no emotion.

"Jobs are on the board. Choose. Not an order from me."

"Report when you return. Alive or as corpses."

"The gate to the Spirit Realm is not something we close. We merely — delay it."

Monk Myoan — an old monk's voice, slow and stretching the ends of words.

"Thirty years ago that night, seven seals were set. I still dream of that night. Every day."

"Patrons. Each lair is a knot in the seal. The more you loosen them... the more the root appears. For good or ill."

Okin, Merchant — fast and practical speech. Calculation behind the smile.

"Information? Three gold coins. Because — this information is worth three coins in blood."

"Weapons are good, but bring antidotes. Poison is fashionable these days."

#Atmosphere Turning Points

New paper on the job board: at the start of a session, the GM reads aloud a new paper posted on the job board. Describing handwriting, stains, and urgency gives player choice weight.

Thickness of the mist: on the morning of departure, hint at danger through the density of the mist visible from the fortress south gate. Thin days tend toward low wilderness-encounter results; thick days tend toward high results. Do not say the number; say, "Today's mist reaches the knees."

Distant bell: when a seal breaks in another lair, a bell rings once in the fortress with no known cause. Myoan lifts his head. This stages the moment the interconnection rule triggers.

Daigongen's tremor: when cumulative sessions reach 10 or more, or when the party approaches a risk 4 lair — the fortress floor rumbles once each night. Water in cups trembles. The time pressure touches the skin.

#Background Music and Color

The dominant colors are stone-wall gray + autumn-leaf orange + blue mist-light. The contrast between these three colors is the heart of the border mood. Indoor(fortress) scenes are the single yellow of lamplight. When entering a lair, reduce the number of colors to one palette(abandoned mine: black+green, ruined temple: white+purple, etc.). BGM image: fortress = slow shamisen pattern, wilderness travel = shakuhachi wind, lair = single taiko strikes. Tone of an open-world epic film, like the morning scenes of Kurosawa's Kagemusha.

---

#Base — Aofu Fortress

#NPCs (7)

Seki Masatora (border warden, samurai 5th dan)

Courage+3, Finesse+1, Physique+3, Wisdom+2, Presence+1
Energy 11, Wounds 7 (3+Physique 3+Tough), Defense 15 (medium armor+shield)

• Fortress commander. Taciturn but fair. Authority to approve jobs.
• Faction trait: Kagura Domain (regular military discipline)

Myoan (esoteric monk 3rd dan, seal master)

• Participant in the great seal 30 years ago. Rich Spirit Realm knowledge.
• Vajra + expected Barrier Master.

Okin (merchant 2nd dan, trader)

• Runs Bizenya shop inside the fortress. Trades weapons/equipment/elixirs.
• Pay 3 gold and designate 1 lair. The next information check about that lair gains +2. This bonus does not stack and is consumed after the check.

Jinpachi (ronin 3rd dan, garrison captain)

• Commands 3 Minion squads. Takes scouting jobs.
• Outer terrain knowledge +3.

Hanabi (entertainer 1st dan)

• The only comfort inside the fortress. Maintains soldier morale with song/dance.
• Healing lull recovery +1.

Tetsu (artisan, Veteran-grade craftsperson)

• Weapon repair, barricade construction.

Genkai (apothecary, medical practitioner)

• Sells herbs. Poison-removal service (1 gold/time).

#Fortress Events (d10 — at session start)

When a new job arrives, determine the target lair with d10.

---

#Lair States and Spirit-Realm Tremor

Each lair has only two states: unsuppressed or suppressed. It becomes suppressed when its master is defeated or its stated objective is completed. A suppressed lair does not return to unsuppressed on its own, and Spirit-Realm Tremor never reverses suppression. Apply only the effects listed in the Lair Interconnections table when a lair's state changes.

Spirit-Realm Tremor is a shared 0~10 campaign clock that starts at 0.

• +1 at the end of every session.
• +1 when the party fails a lair assault and retreats or is wiped out.
• +1 when fortress event 10 occurs.
• At 10, Daigongen awakens and Lair 7 opens. This does not prevent an attempt to restore the seal.

Lair 7 also opens, as before, when the Spirit-Realm Tremor clock reaches 10 or once at least 4 other lairs are suppressed. Meeting either condition is sufficient.

---

#Wilderness Encounter Table (d100, during travel)

---

#7 Lairs (Risk 1~4)

#Lair 1 — Kooni Boss (Risk 1, 1st dan)

• Location: 30 ri southwest of the fortress. Small cave.
• Master: 1 Oni Warrior commands 2 kooni squads.
• Reward: 10 gold. Kooni diary (connected to Lair 3).

#Lair 2 — Onryo Warlord (Risk 2, 2nd~3rd dan)

• Location: abandoned castle site. North of the fortress.
• Master: Onryo Warlord (Elite, Wounds 3, Defense 15, Energy 8, 50% incorporeal).
• Challenge: Exorcism Licensed(3 points)+ recommended ([Incorporeal] attacks use normal Defense). Even Novice(1 point) can provide partial protection(-2). §Exorcism Exemption Table.
• Reward: onryo armor (masterwork armor). 20 gold.

#Lair 3 — Spider Shrine Maiden (Risk 3, 3rd~4th dan)

• Location: eastern ruined temple.
• Master: Spider Shrine Maiden (Elite, Wounds 4, Defense 14, Energy 10). Poison insects + spider silk.
• Challenge: Core Zone(altar) control fight.
• Reward: secret of poison antidotes. 30 gold.

#Lair 4 — Mine Master (Risk 2, 2nd~3rd dan)

• Location: abandoned mine. Western mountain.
• Master: Gama-kishin (Veteran, Wounds 3, Defense 12, poison smoke).
• Special: sealed mine structure — Core Zone movement restriction. Firearms are dangerous.
• Reward: gold-vein map (linked to Domain Management).

#Lair 5 — Shirogumo (Risk 4, 4th dan+)

• Location: deep forest. Far northeast of the fortress.
• Master: Shirogumo (upper Elite-grade, Wounds 5, Defense 15, Energy 11).
• Warning: PCs below 4th dan are in danger. Avoid approach recommended.
• Reward: Shirogumo silk(masterwork material). 50 gold.

#Lair 6 — Necromancer (Risk 3, 3rd~4th dan)

• Location: beneath the graveyard.
• Master: Necromancer (Elite human Shikome-no-Tsukai, Wounds 4, Defense 14, Energy 10).
• Challenge: 1 shikome from Shikome Servitude is already deployed when combat begins. Only after that shikome becomes incapacitated may the necromancer pay 3 Energy during the Lull Phase to resummon it. There is no free summon every round.
• Reward: ghost-sealing book. 40 gold.

#Lair 7 — Daigongen (Risk 4, 5th-dan lord-grade)

• Location: mountaintop shrine ruins.
• Master: Daigongen (lord-grade, Wounds 7, Defense 16, Energy 12).
• Core: source of the great seal 30 years ago. Climax lord-grade enemy.
• Approach: opens after at least 4 other lairs are suppressed or the Spirit-Realm Tremor clock reaches 10.
• Reward: fundamental solution to the Spirit Realm rift. Campaign completion.

---

#Lair Interconnections

---

#Step-by-Step Progression Guide

Because of its sandbox nature, there is no traditional "act" structure. Instead, divide the campaign into 4 stages by risk and advancement baseline. Each stage is entered through PC growth and accumulated lair suppression, not through session count alone.

#Act 1 Progression Guide — Exploration Stage (Sessions 1~4, PC 1st~2nd dan)

• Success branch: suppress Lair 1 + obtain kooni diary → secure clue to Lair 3. Lair Interconnections table automatically triggers.
• Failure branch: all PCs reach Wounds 0 in Lair 1 → Jinpachi's rescue team transports them to the fortress. Fame -1, and Okin advises, "Next time, antidotes first." Failure is learning, not elimination.
• GM control: (1) During the first 3 sessions, leave the danger-level 4 lairs (5 and 7) open, but do not send the party into them immediately. Myoan provides a natural guard by saying, "It is not time yet." (2) If the job-board d10 gives 3, the GM may gently steer toward a lair the PCs show interest in.

---

#Act 2 Progression Guide — Investigation Stage (Sessions 5~10, PC 2nd~3rd dan)

• Success branch: suppress 2~3 mid-risk lairs → seal knowledge accumulates. Myoan begins explaining the structure of the great-seal restoration rite. PCs reach 3rd dan.
• Failure branch: if a lair assault fails, that lair remains unsuppressed and Spirit-Realm Tremor +1. Do not add a separate Energy increase or a new summon; show time pressure through the tremor clock and changes on site.
• GM control: (1) Do not reveal the Interconnection table to players. Let them discover on site that "after striking Lair 1, something changed in Lair 3." (2) If there is too long a gap between sessions, maintain bonds through personal RP scenes with fortress NPCs — Hanabi's performance, Myoan's dream story.

---

#Act 3 Progression Guide — High-Risk Stage (Sessions 11~15, PC 3rd~4th dan)

• Success branch: suppress Shirogumo or Necromancer + gain Daigongen Defense -1 through interconnection → condition to enter Act 4. Myoan reveals the full text of the great-seal restoration rite.
• Failure branch: possible PC 1 Wound 0 death against Shirogumo → introduce replacement character(from the 7 Aofu NPCs). No reputation change; only emotional impact. Void 1 accumulates in Three Ways and Six Hearts.
• GM control: (1) The GM warns before risk 4 lairs — through Jinpachi's mouth, "Below 4th dan is dangerous." If they enter anyway, run cold by the rules. (2) At this stage, reveal the Spirit Realm tremor count to players too. Time pressure should function as a strategic element.

---

#Act 4 Progression Guide — Climax (Sessions 16~20+, PC 4th~5th dan)

• Success branch: defeat Daigongen + restore the great seal → peaceful ending. Sekimori border reputation +5, Kagura Domain +3. Remaining lairs fade naturally(slowly lose power). Domain Management hook opens.
• Failure branch: Daigongen breaks the seal and descends to the surface → Spirit Realm chaos ending. New campaign begins with Aofu Fortress becoming the last defense line. Three Ways and Six Hearts expands toward Demon; those who upheld Loyalty take the road of rebuilding.
• GM control: (1) The great sealing rite's 3 rounds are the most dramatic section. If Myoan falls during the rite, one PC may substitute with a Child of Scripture/Barrier Novice check. (2) Final section where PC death may be allowed. But if they die, make it meaningful — taking an enemy attack for someone else, or filling the rite's final seal with their body.

---

#Sandbox Play Guide

• 1 job per session: too many parallel lairs causes confusion. Suppressing one lair every 3~4 sessions is appropriate.
• Recommended exploration order: early play is safest as Lair 1 → Lair 2 or 4 → Lair 3 or 6 → Lair 5 → Lair 7. During the first 3 sessions, warn the party about Lair 5's danger and show only sealing clues for the still-locked Lair 7.
• Return to fortress: treat as session-end upkeep, separate from combat lull. Handle rest, shop use, equipment repair, and taking new jobs as one bundle.
• Voluntary direction: PCs decide lair order. The GM reflects suppression results into the world.
• Spirit-Realm Tremor: use the 0~10 clock above to make the time pressure visible. At 10, Daigongen awakens and Lair 7 opens, but an attempt to restore the seal remains possible.
• Pregens: some of the 7 Aofu NPCs can be used as PCs (replacement characters).

---

#Reward Summary

• Gold total: about 150 gold for suppressing all lairs (can be invested in Domain Management).
• Masterworks: onryo armor, Shirogumo silk(crafting material).
• Information: ghost-sealing book, gold-vein map, great-seal restoration rite.
• Fame: Sekimori border +5, Kagura Domain +3.
• Advancement progress: expected 1st~5th dan. PCs complete a full growth arc across the campaign.