Reception devlog · Feature

Monsters by the numbers

October 21, 2026 · BellHop Studios

Reception has three monster species today: the rat, the bat, and the ghoul a bat becomes. Here is how they are built, how they grow on the map, and how simulated fights, not feel, set their numbers.

A species and a tier

Monsters have no class. They use the same six stats as heroes (HP, ATK, DEF, MAG, RES, LUK), and a tier multiplies the species' stats: a stat at tier t is the base stat times (1 + 0.25 t), rounded, where Common is 0, Elite 1, Champion 2 and Boss 3.

A species can promote. A bat that reaches Champion changes form into a ghoul, and uses the ghoul's base stats under the same multiplier. Only the spawning species ever spawns, so a ghoul exists only because bats won. Name, art and tier word follow the form: a bat at absolute tier 2 is shown as a Common Ghoul, while its stats, abilities, tokens and drops keep keying off the absolute tier.

The jump from an Elite bat at 10 HP to a Champion ghoul at 83 is deliberate. It is the Bat Fields' signature spike, and the sign that it is time to leave.

Five abilities, each with a price

Monster abilities are given per form, each from a minimum tier, so a unit grows new actions as it is promoted.

A monster unit's Gear Score is its stats on the monster table, plus the GS of every ability it knows (decided 2 October). Stats alone read a ghoul badly wrong, because its danger is a bleed that will not close and a thirst that undoes the party's healing.

How the numbers were tuned

• Bats, 26 September. Raised from 7 / 4 / 1 / 0 / 2 / 4 to 8 / 6 / 2 / 0 / 2 / 6, so a Common bat (GS 15) sits clear of the rat and the 1.25 step lands an Elite exactly on GS 22.
• The ghoul's first draft could not land. At 20 HP, 6 ATK and 4 DEF it died in one hit, because a 250 GS party has about 38 ATK. It was resized against a half-cap party on 22 September, to 55 / 18 / 16 / 6 / 10 / 1 before the tier multiplier.
• Ghoul RES fell from 10 to 4, 2 October. Because damage is subtraction, every defence is a threshold. At RES 10, a Champion ghoul's RES of 15 was above a starting mage's whole MAG of 9, so a party went from a 15% win rate at 174 GS to 100% at 200 GS with nothing in between. At RES 4, magic rises from 13% to 44% of a party's damage, and the same three parties win 65, 100 and 100 percent of the time. The rule that stayed: keep ghoul RES below the weakest starting mage's MAG, and add menace with HP or DEF instead.
• Measured on 1 October: about 200 GS beats a lone ghoul, and about 260 beats a pack.

Monsters on the map

On a field, monsters live as groups of one to four units. Groups move on their own clock, grow by meeting each other, and start a fight when they reach a party. A group's tier is earned on the map. That is how a field full of Common bats ends up with ghouls in it.

• Rat Fields: 120 groups at generation, every one a single Common rat.
• Bat Fields: 100 groups. Their starting tiers are weighted 50 / 25 / 19 / 6 from Common to Boss, and their starting sizes 50 / 28 / 15 / 7 from one unit to four. The reason: a run of about 250 ticks ends before a swarm can grow a ghoul, so the cavern starts "screaming", with about one group in eight already a ghoul.
• Respawns. When the living count falls under 60%, the field respawns monsters as fresh Commons. What a field grows during a run is still earned.

Merging and promotion. When two groups meet, one of three things happens:

1. Absorb. If either is a lone unit and neither is full, the lone one joins the other, up to four units.
2. Power-up. Otherwise the stronger group wins, scored as tier times 100 plus size. One random eligible unit in it goes up a tier, and a bat reaching tier 2 becomes a ghoul.
3. Stat-absorb. If every unit is already at its cap, the group's Boss permanently absorbs a share of the loser's stats instead. The share shrinks as it nears the field's Boss cap: 250 GS on the Rat Fields, 625 on the Bat Fields, counting its abilities.

Movement. Every group goes through the same steps: cadence, treasure pickup, merges, fight triggers. Only the choice of direction differs, by the field's movement model:

The two newer models came out of two research memos in September, one on Mystery Dungeon and one on how peer games run their monster AI. Species settings move them: bats step every 2 ticks and ghouls every 5, and a group moves at its slowest form, so a ghoul can never run a party down. Rats see 2 tiles, bats 3, ghouls 4. Rats wander 15% of the time, bats 35%, ghouls never. A lone unit moves every 4 ticks, a group of three every 2, and a full group every tick.

Tokens and jobs. A killed monster can leave a token behind: a Rat Tooth, a Bat Wing, or a Ghoul's Skull from tier 2 up. A party carries tokens home, and a rival party can steal them in PvP. A field's jobs ask for tokens: an Errand for 3, a Contract for 8, and a Trophy for 1 skull. Making tokens the jobs, on 4 October, replaced the whole earlier assignment ladder. Ghoul Bosses on the Bat Fields also drop the four tier-5 special gear pieces.

Numbers set by simulation

Numbers in Reception are set by simulation, not by feel. On-demand harnesses play thousands of real fights through the same engine the game uses. Unit tests then pin the results and the rules, so a later edit cannot drift without a red build.

What the measurements taught

• Defences are thresholds. Damage is subtraction, so below an attacker's line every hit is 1, and one point above it the attacker works. A fight against one armoured unit is a cliff, not a slope.
• Win rate cannot price an ability. It priced a 3 GS trinket and a 25 GS mauling the same, so abilities are priced by the health a fight costs instead. Measure against a party that has to work for the win, or an ability reads as worth nothing.
• Build the measuring party for its roles, not for GS. Gearing greedily by GS poured everything into the hunter and left the mage at bare MAG. That once wrongly reported that halving ghoul RES changed nothing.
• Per-unit targets are not run targets. Five fights at 95% each is a 77% run. Set each creature to the rung targets, then tune the population against a run-level wipe rate.
• The flat +25% tier step is the wrong shape at both ends. It is too shallow for a third field (about +40% fits) and leaves a Champion cliff in the planned Outskirts. A per-species step is proposed, not built.
• GS is additive and blind to matchups. It cannot see that one ghoul is harder than four weaker bodies of the same total, or that casters suit spell-armoured foes. Better prediction needs a health-times-damage term, not a bigger weight.
• A win does not prove an ability fired. The training sweep diffs every beat to catch silent no-ops. That is how it found three abilities misbehaving, and the hunter's zero-damage hits.
• Keep the random draws stable. Banner and Mettle hooks replace an existing draw instead of adding one, and a test counts the draws, so seeded harness runs stay comparable after a change.

Rules for tuning a monster, set on 2 October:

• Either side, never both. A monster is armoured against blades (DEF) or against spells (RES). The smaller of the two is at most 40% of the larger, or 3, and a test enforces that for the whole roster at every tier.
• Only the armoured side scales. It grows with the rung; the open side stays flat.
• Tune per unit, then density. Per-unit targets come first, then the number and size of groups is tuned to a run-level wipe rate. The Bat Fields precedent is 12% wipes for a half-cap party.
• Price every ability in GS before shipping it.

Gear Score itself was checked against outcomes too. An HP weight between 0.05 and 0.15 predicted fight results best, so raising the hero and monster HP weight was rejected on 11 October. Only the gear table moved, to 0.2, when the Quilted HP line was measured against the standard Common set.

Questions still open

• A per-species tier step, for any field beyond the Bat Fields.
• A concentration term in monster GS, because one ghoul beats parties scored well above its 116.
• Magic-attacking monsters. There are none yet, so a hero's RES does little against monsters today.
• Leader orders for hunters, mages and clerics, which still lead with the older Banners.
• What Loose Rein should cost in combat.
• Mixed-species groups, for the 50 planned monsters. Only the Outskirts band has stats so far, and the engine can't form a mixed group yet.

How the monsters evolved

• 20 OctoberDungeons carry their field's cap. The Cellar 200 GS, The Belfry 500.
• 11 October50 named monster concepts in five bands, with stat lines for the first band, the Outskirts. On paper only.
• 9 OctoberDungeon tiers 1 to 3, each a new run. Tier 2 gives monsters 30% more GS spread evenly, Tier 3 a further 30% on their best three stats. A first build with a flat +25% and +50% toggle was dropped within half an hour.
• 6 OctoberGroups form up. A Boss stands in slot 2 behind a shuffled escort, where neither warriors nor hunters aim. Ghoul tier names count from the ghoul's own first rung.
• 4 OctoberTokens replaced the assignment ladder. Teeth, wings and skulls became the jobs.
• 2 OctoberMonster GS counts abilities. Ghoul RES cut from 10 to 4, so magic is the way in. The creature design rules: one armoured side, rung targets.
• 1 OctoberMeasured: about 200 GS beats a lone ghoul, about 260 a pack.
• 26 SeptemberFirst monster abilities. The rats' Poison Bite and Over Bite; the bat line's Bleeding Bite, Red Drinker and Blood Rage. Bats raised to GS 15 and 22.
• 22 SeptemberMovement models per field (Baseline, Mystery, Trail) and the headless lethality harness. The ghoul resized from 20 / 6 / 4 / 2 / 3 / 1 to 55 / 18 / 16 / 6 / 10 / 1. The Bat Fields start with ghouls and packs on the floor.
• 20 SeptemberThe bat line settled: bats at Common and Elite, ghouls at Champion and Boss. The Bat Fields capped at 500 GS.
• 19 SeptemberThe Bat Dungeon designed, now the Bat Fields: only bats spawn, and bats that win promote into ghouls.
• 1 SeptemberPopulation raised from 40 to 120 groups, aiming at about 20% of runs with no fight. Every beaten group pays at least 1 treasure.
• 30 JulyOne Boss per group. A Boss absorbs a beaten enemy's stats, capped at 250 GS after an uncapped version lasted two hours.
• 29 JulyMonsters stopped healing to full after a win. Damage carries between fights. Minimum damage of 1 confirmed.
• 28 JulyThe first species, the Rat (8 / 3 / 2 / 0 / 1 / 2). Groups fight as separate units, power-ups promote one random unit, and big groups hunt and move faster.
• 27 JulyStatic enemy tiles replaced by 40 roaming monsters that merge into groups of up to four and gain tiers: Common, Elite, Champion, Boss.
• 26 JulyDay one: a watch-only simulation with static enemy tiles and no combat.

The heroes' half of this machine, the stats, the classes and the order of authority on every beat, is in How a fight works. For the story of how all of this got built, start with How Reception was built. If you'd like to advise on it or help build it, write to support@bellhopstudios.com.