Chapter 1: Session Zero

A Session Zero is the first gathering of your group, before anyone rolls dice. Its goal is to make sure everyone at the table feels safe, excited, and on the same page about the story you're about to tell together. Run this even if you've played with the same people for years — every campaign is different.

Session Zero Checklist

1. Introduce the world in one sentence. "You're adventurers in a world three times the size of Earth, where gods walk the sun and dungeons are alive."
2. Explain the tone. Is this campaign heroic, grim, comedic, political, or a mix? Give a touchstone: "It's like Castlevania meets Princess Mononoke."
3. Discuss content and boundaries. Hand out the Trigger Warning Form (below). Explain Lines (topics that will never appear) and Veils (topics that can exist but happen "off-screen"). Establish the X-card rule: anyone can pause the game at any time, no questions asked, by tapping an X-card or simply saying "pause."
4. Set PvP policy. Are player-versus-player actions allowed? If so, under what conditions? The default for Fheros is: PvP requires explicit, enthusiastic consent from both players and the GM at that moment.
5. Discuss house rules. Will you use encumbrance? How strict are rests? Are certain Arts or species restricted?
6. Create characters together. Players don't need to finish their sheets, but they should decide on species, mastery, and party role together so the group has a reason to adventure as a team.
7. Set the first scene. End the session by placing the party in a location and giving them one immediate goal. "You're in the guild hall of Nautilus. The quest board has one job left: a missing caravan on the forest road. The reward is 1d4 Iron coins. What do you do?"

Printable Trigger Warning Form

Give this to each player before the campaign begins. They can fill it out privately and return it to you. Marked items will be completely absent from the game.

Chapter 2: Running the Game

The Core Mechanic

Whenever a character attempts something with a chance of failure, roll a d20, add the relevant Action stat modifier (and your Proficiency Bonus if you are proficient), and compare the result to either the target's Defence or to a Reaction DC set by the GM.

Attack rolls: d20 + Action stat mod + Proficiency (if proficient with the weapon) vs target's Defence.

Skill checks: d20 + Action stat mod + Proficiency (if proficient in the skill) vs a GM-set DC.

Reaction checks: the target rolls a d20 + relevant Reaction stat mod. If the roll equals or exceeds the attacker's Effect Save DC (8 + Proficiency Bonus + Rank), the effect is resisted or halved.

Stats and Modifiers

There are 8 core stats, split into Action (used to do things) and Reaction (used to resist things).

Modifier: Stat divided by 2, rounded down. This modifier is added to all relevant d20 rolls.

Proficiency Bonus

Formula: your Rank + your highest Action stat modifier. This number is added to attack rolls with proficient weapons, skill checks with proficient skills, and your Effect Save DC.

Skills and The PTEL System

At character creation, you have 8 + Knowledge modifier skill points to spend (minimum 0).

Action Economy

On your turn in combat, you have:

• 3 Actions – Attack, cast a spell, use an item, dash, disengage, hide, or help.
• 1 Bonus Action – quicker actions: certain attacks, Tricks, drinking a potion, giving a short command.
• 1 square of movement – 1 square = 10 m by 10 m. If you have fly or swim speed, the square becomes a 10 m cube.
• 1 optional skill check – can be attempted without spending an action.

If you follow an Adrenalium Mastery path (Berserker, Combatant, Martial Artist, or Stealth), you gain +1 Action, +1 Bonus Action, and +1 square of movement each turn.

Defence and Armour

Defence (DEF): 10 + the higher of your CON or DOD modifier. This is the number an attacker must meet or beat.

Armour: a flat value from equipment or traits. When you take damage, subtract your Armour value except from Mystic (Eclipse, Psychic, Lies) and Power (Radiant, Force, Necrotic) damage.

Arcanium and Adrenalium (Source Points)

Your magical or martial energy pool.

Arcanium (spellcasters): max = 20 + (CRE or KNO + Proficiency Bonus) x 10.

Adrenalium (martials): max = 20 + (STR or DEX + Proficiency Bonus) x 10.

Source Points: the combined pool; spent to cast spells or perform martial techniques. Recharges on rests.

Rest and Recovery

Short Rest: recovers 50% of max HP and 50% of max Source Points.

Plentiful Rest (Long Rest): recovers 100% of max HP and 100% of max Source Points. If fewer than half the party sleeps, recovery is limited to 75%.

Dying Rules

The first time you drop to 0 HP after a rest, you instead drop to 1 HP. If you fall to 0 HP again before resting, you begin making Death Saves (GM's call).

Player Character Death

Death is not the end, but it is serious. When a character dies:

• Their Source travels to Zaheer's Afterlife. The player may roleplay a brief scene in Exolvuntis or before the relevant Sin Ruler.
• Resurrection is possible but requires a quest: travelling to The After, petitioning Zaheer or Kaitlyn Booman (The Scythe), or retrieving the Source from Carceris. No spell simply brings someone back — the party must earn it.
• If the party cannot or will not pursue resurrection, the Source is purified in Exolvuntis and eventually reincarnated. The player creates a new character, who may have fragments of the old one's memories (GM's discretion).
• Only a wish, a god's help or a Mythril level pantheonic spell caster can revive you from death.

NPC Death and Undeath

NPCs follow the same rules. Villains who die may become undead if their Source crystallises rather than passing on. This is especially common for those killed by necromantic weapons, those who die in the Sanctuary of Zaheer, or those who have made pacts with the Skion Clan. A dead villain is not necessarily a finished villain.

Inspiration

When a character does something clever, heroic, or dramatically appropriate, the GM may award Inspiration. The player can spend it to add 1d4 to any d20 roll they make. A player can hold only one Inspiration at a time.

Range Bands

Close: 1 square (10 m) | Mid: 3 squares (30 m) | Long: 9+ squares (90+ m)

Chapter 3: Between Sessions

Downtime Activities

When the party rests in civilisation between adventures, offer them downtime choices:

• Crafting: Use looted body parts and gold to commission or create magic items (requires appropriate tools and sufficient time).
• Research: Spend time in a library or temple to learn about a relic, a god, or a villain. Grants advantage on relevant Knowledge checks for the next adventure.
• Training: Work with a mentor to swap one Trained skill for another, or to gain proficiency in a new tool. Requires a fee and 1d4 weeks.
• Networking: Build relationships with a faction. May yield future allies, discounts, or plot hooks.

Session Pacing

First 30 minutes: Recap, warm-up roleplay, set the immediate goal.

Middle 2 hours: The adventure's meat — exploration, combat, discovery.

Final 45 minutes: Climax or cliffhanger, loot distribution, downtime decision, and a teaser for next session.

Always end on a question: "The door swings open. Beyond it, you hear a child crying. What do you do?" Let them sit with that until next time. See it as homework that makes them think about your game.

Chapter 4: Additional Guidance

Adjudicating the Unusual

Players will inevitably attempt things not covered by the rules. When they do:

• Is it possible? If the action is within reason (even if highly improbable), allow a roll. If it's physically impossible or contradicts established lore, just say no — but offer an alternative.
• Which stat applies? Use the stat that best matches the intent: Strength for breaking things, Dexterity for balancing, Knowledge for recalling lore, Creativity for persuasion.
• Set the DC. 10 for easy, 15 for moderate, 20 for hard, 25 for heroic, 30 for legendary.
• Determine consequences. Failure doesn't always mean nothing happens — sometimes it means progress with a cost, a complication, or lost time.

Running Combat Efficiently

• Group initiative: Players act as a team, choosing their own order each round. Enemies act on a single GM initiative count (usually after the first player action). This speeds up play dramatically.
• Announce intent, then resolve: Ask "What do you do?" before rolling. Resolve all three actions together if possible, not one at a time.
• Use average damage: For large groups of low-Rank enemies, skip the dice and use the average value. A swarm of Paper-Rank goblins always deals 6 damage per hit — move on.
• Momentum: If a player describes a creative or cinematic action, grant Inspiration or lower the DC. Reward engagement.

Running Social Encounters

Not every conversation needs a roll. Let roleplay carry the scene. When dice are called for:

• One roll can cover an entire negotiation unless the situation escalates.
• Use Creativity (CRE) for persuasion, deception, intimidation, or charm.
• Use Knowledge (KNO) for logical arguments, legal debate, or recalling relevant facts.
• Attitude matters: Hostile NPCs impose disadvantage. Friendly NPCs grant advantage. Indifferent NPCs are neutral.
• Failure doesn't end the scene: It changes the terms. The NPC may demand a favour, raise the price, or require proof of good faith.

Exploration and Travel

Getting from one place to another is an adventure in itself. Use a simple rhythm:

• Set the scene: describe the environment, weather, and any visible landmarks.
• Ask for roles: who is navigating (Knowledge/Survival), who is keeping watch (Perception), who is foraging or scouting ahead?
• Roll once per leg of the journey (not once per day). On a failure, introduce a complication: a hazard, a lost trail, a wandering creature, damaged supplies.
• Offer meaningful choices: the safe road through civilisation costs coin and time; the dangerous shortcut through the wilds costs risk.

Chapter 5: Worldbuilding on the Fly

Improvising NPCs

When players ask for a name you didn't prepare, give one immediately. A dwarf blacksmith in Dur'Ned might be "Greta Val Coppervein," always wiping soot on her apron, allergic to silver, and secretly in love with the baker across the bridge. That's all you need — name, job, one physical detail, one quirk, one secret. Everything else can emerge in play. Use the Random npc generator on my website if you are really in a pickle.

Improvising Settlements

For a town you didn't plan, answer three questions:

1. What do they produce or trade? (This tells you why the town exists.)
2. Who is in charge, and who resents them? (This gives you conflict.)
3. What rumour does every local know about the nearby wilderness? (This gives your players a lead.)

Using the Lore Bible at the Table

The full Lore Bible is a reference, not a script. When you need to answer a player's question about a god, a city, or a historical event, look it up — but don't read the entry aloud. Translate the lore into a sentence a local would actually say. "The Queen of Shards arrived 2,550 years ago through a fey portal and conquered Mountside" becomes a tavern rumour: "They say the elf queen came through a hole in the sky and turned the old human capital into a forest overnight. My grandmother's grandmother saw it."

Chapter 6: Quick Reference and GM Screen

Conditions

Physical

Mental

Damage Types

Physical damage: Impact, Slashing, Bludgeoning, Piercing, Lingering, Internal.

Armour bypass: Mystic and Power types ignore Armour.

Coinage

Reaction DC and Effect Save DC

Reaction check (creature resists): d20 + relevant Reaction stat mod.

Effect Save DC (spells/abilities): 8 + Proficiency Bonus + Rank.

Size Classes

Chapter 7: Building Adventures

Example Plothooks for Every Rank

Each hook is designed for a party of the given rank. The "twist" is optional — use it if your players enjoy intrigue or unexpected turns. The blank space at the end of each hook lets you personalise the adventure for your table. First batch are mild, second batch is to challenge your players.

Copper — The Missing Shipment

Iron — The Howling Mines

Steel — The Possessed Heir

Silver — The Tide of Teeth

Electrum — The Sky-City's Cry

Gold — The Dragonvault of the Red Brother

Platinum — The Emperor's Scales

Mythril — The Anvil's Call

Challenging Plothooks

Copper — The Cradle of Ashes

Iron — The God in the Gears

Steel — The Feast of One Hundred Hearts

Silver — The Song That Ends the World

Electrum — The Parliament of Bones

Gold — The Library of Unwritten Pages

Platinum — The Last Dragon's Egg

Mythril — The Key to the Cage

Dungeon Delving

What Is a Dungeon?

In Fheros, a dungeon is not a cave. It is a demiplane — a pocket of reality folded into a space far larger than its entrance suggests. But their true origin is older and stranger than mere arcane accident.

Dungeons are the tears of Everblue. The moon goddess — the bright face of Tsukimichi — sheds them across the surface of Fheros like drops of divine sorrow. Where a tear falls, reality warps. A demiplane unfolds, larger within than without. At its heart, a Dungeon Core forms: a crystalline nexus of mana, semi-sentient, pulsing with the goddess's hidden grief.

Everblue is the goddess of the moon, of secrets, and of hidden things. She is also the greatest secret herself. The moon goddess Tsukimichi is two beings in one body. The bright face — serene, silver, worshipped by dragons on the far side of the world — is Everblue. The dark face — bitter, raging, sealed inside the lunar sphere — is Serma, the ancient betrayer goddess of Sun and Moon. Mellia believes Everblue is a new goddess who rose to replace the traitor. She is wrong. Everblue hides Serma within herself, and every dungeon on Fheros is a tear shed by a goddess who cannot show her true face.

Everblue does not control dungeons. She weeps them. Mortals can become dungeon masters by claiming a core, and the goddess does not interfere. Her role is that of a distant, sorrowful mother — she creates secrets, and she blesses those who hide things, but she does not manage what grows from her tears.

How a Dungeon Works

The Core: At the heart of every dungeon lies its Dungeon Core — a crystalline nexus of mana that anchors the demiplane to reality. The core is the dungeon's brain, its heart, and its womb all at once. It extrudes chambers, corridors, traps, and treasures according to its Rank, growing in size and complexity as time passes or as challengers delve deeper.

Emulation, Not Creation: The monsters within a dungeon are not truly alive. They are emulations — projections drawn from the dungeon's memory, perfect copies of creatures that exist or once existed outside the dungeon. When slain, they dissolve into shimmering magic and leave their loot neatly arranged on the floor. No butchering is required; the dungeon rewards its challengers by design. This is the fundamental difference between a dungeon monster and a wild monster: one is a projection that drops loot automatically, the other is a real creature that must be carved apart for its valuable parts.

Dungeon Masters: Every dungeon core can bond with a mortal — intentionally or accidentally — creating a Dungeon Master. The Master gains total awareness and control over the dungeon's layout, its creatures, and its traps. More often than not, the Dungeon Master serves as the final boss of the dungeon. Claiming a core requires defeating or supplanting its current Master, or bonding with an unclaimed core before it develops its own rudimentary will.

Dungeon vs. Civilization Core

A Civilization Core is the opposite of a Dungeon Core. Where a dungeon generates chaos, monsters, and treasure to lure adventurers, a civilization core generates order, protection, and the infrastructure that sustains a city — roads, wards, weather control, and communal magic.

From Dungeon to Civilization. When a dungeon is cleared — its master defeated, its core claimed or shattered — the crystal goes dark. This dead core is inert, but not useless. Mortals have learned to take these dead dungeon cores and refine them through arcane rituals and pact-magic into Civilization Cores. Where the old core extruded monsters and traps, the new core radiates life: it repels mindless creatures, purifies water and soil, and — most critically — causes every living being born within its reach to be born with a Source. This is the fundamental difference between a camp and a nation. A camp is a place where people survive. A city with a core is a place where people are born as true Persons, with souls that will one day journey to Zaheer's Afterlife and return.

Civilization cores require no fuel, no priesthood, and no maintenance. Their power is sustained by the simple cycle of life: the birth and death of the citizens who dwell within their aura. A core grows in strength as the population grows; Xevis, the elven capital, possesses a mythril-level core that has pulsed for two and a half thousand years. An abandoned core, left without mortal life, slowly reverts over decades into a dungeon core. A destroyed core plunges the land into hardship — crops wither, monsters return, and children are born without Sources — but the land does not die. It simply becomes wild again.

Mekhis, the god of artifice, sometimes assists in the rituals that refine dead cores, but his involvement is practical, not divine. Civilization cores are ultimately a mortal achievement, built from divine sorrow, blessed by a goddess who hides her own darkness behind a silver smile.

The presence or absence of a core defines whether a settlement is merely a camp or a true nation. Adventurers are often employed to clear dungeon cores so that civilization cores can be safely established nearby. This is one of the primary functions of the Adventurer's Guild.

Dungeon Structure by Rank

Each Level of a Dungeon Contains:

• Entrance / Threshold: a clear signal that you've crossed into the dungeon's domain. The air changes. The walls are alive. The door locks behind you.
• Guardian: the first combat test of the level. Usually a creature or group slightly below the level's average difficulty, to teach the party what to expect.
• Museum / Puzzle Room: a space that rewards exploration and intellect over combat. Lore carvings, hidden levers, environmental storytelling. Failure here costs resources or triggers a trap; it does not usually kill.
• Stagger Levels / Multiple Floors: a single "level" of a dungeon may span several floors connected by stairs, shafts, or teleporters. Each floor has its own identity but shares the same core thematic challenges.
• Social Encounter: not every resident is hostile. A trapped adventurer, a bored demon, a talking door — something that can be reasoned with, bribed, or tricked.
• Treasure Vault: a mid-level reward. Contains currency, consumables, and sometimes a permanent magic item.
• Boss Room: the climax of the level. The boss has Epic Actions and often Lair Actions. Defeating it (or sometimes convincing it) grants access to the next level.
• Core Shard (optional): a fragment of the dungeon's power source. Destroying or claiming it may alter the dungeon permanently. Destroying the core destroys the dungeon.

Dungeon Loot

Unlike surface monsters, dungeon creatures drop loot automatically — neatly arranged coins, scrolls, and items that appear in a puff of magic upon their defeat. This is the dungeon's reward system. Bosses drop signature magic items and 1d4 body parts that can be used for crafting (even though the creature itself was an emulation, the dungeon replicates physical components that remain real after death). The final core vault contains the dungeon's true treasure: 3–6 permanent magic items, 9–12 consumables, and a hoard of coins and gems appropriate to the Rank.

Encounter Building

• Small encounter: 1–2 creatures of the party's Rank, or a larger number of lower-Rank creatures.
• Medium encounter: equal number to the party, same Rank.
• Hard encounter: 1 creature 1–2 Ranks above the party, or multiple same-Rank with tactical advantage.
• Boss encounter: 1 creature 2+ Ranks above, with Epic Actions and Lair Actions. Adjust HP upward by 20–50% for solo bosses.