The Monster-Hunter Cell

This is V5's systems engine. Where the Urban-Crime cell lives or dies on the texture of a city, the monster-hunter cell — V5's Witcher surface — lives or dies on a single loop the design treats as sacred: read a contract, track the beast, name it, brew against it, then fight a thing you have already half-beaten at the alchemy table. Battle-prep is half of every monster contract here. A drowner in a flooded crypt and a wyvern on a wind-scoured plateau are not just different health bars; they want different oils on your silver sword, different bombs in your pouch, different signs held to a full stamina bar, and a different page of the bestiary filled in before the damage multiplier even turns on. It is the most mechanically dense of the five ruleset cells — four shared mechanic cores stacked under one campaign — and it is the cell that proves V5's second thesis: that the same engine wearing a crime sandbox elsewhere can also wear a patient, knowledge-gated action-RPG where preparation is the content.

The cell ships as a Witcher-3-style campaign composition module (V5HunterWitchersPath) plus three procedural satellite surfaces — a contract board (V5HunterContractBoard), a gwent-style card minigame (V5HunterCardGame), and a permadeath roguelike (V5RoguelikeHunterRun) — all composed over four shared C++ mechanic cores: V5Alchemy, V5Signs, V5MonsterHunt, and V5Hunting. The promise is a preparation loop where every system feeds the next: the bestiary tells you the monster is weak to a specter oil, the oil comes out of an alchemy recipe, the recipe wants three foraged ingredients on a respawn timer, and casting a sign mid-fight spends from the very same stamina pool that your dodge regenerates. This page inventories what that stack does on the player's side of the screen and points at the exact Unreal C++ behind each verb. For the full mode taxonomy, roster, and the scope this slots into, start at the hub: ../V5_features.md.

What ships, honestly#

The cell's mechanics are real, compiled, and tested. Every module named above exists under V5/ue/Source/ with a Public//Private/ split, a *.Build.cs, and a Private/Tests/ automation spec, and the linker has been through them on this box: libUnrealEditor-V5Alchemy.so, -V5Signs.so, -V5MonsterHunt.so, -V5Hunting.so, -V5HunterWitchersPath.so, -V5HunterContractBoard.so, -V5HunterCardGame.so, and -V5RoguelikeHunterRun.so all sit in V5/ue/Binaries/Linux/ next to their sources (the campaign module is the heaviest at ~891 KB), built by the ueagent user. The signature math is real domain-specific code — a 70 %-toxicity self-damage threshold, a 1.2× knowledge-gated damage bonus, a three-condition perfect-pelt classifier, a deterministic seeded roguelike score — and each is pinned by UE IMPLEMENT_SIMPLE_AUTOMATION_TEST assertions that check values, not truthiness (TestEqual("Completed bestiary grants 20 percent damage bonus", …, 1.2f)).

The data is C++/JSON catalogs; the art is not in-tree. Consistent with the rest of V5's 0-binary-.uasset accounting — a find over V5/ue/Content returns zero cooked .uasset files — the catalogs that drive these systems ship as version-controlled JSON and are validated hard: Content/V5Alchemy/Data/alchemy_catalog.json (84 KB), Content/V5MonsterHunt/Data/monster_hunt_catalog.json (44 KB), and Content/V5Hunting/Data/hunting_catalog.json (43 KB). So the logic and balance of every signature system is real, while the meditation-pose brewing montages, monster meshes, sign Niagara systems (referenced by FSoftObjectPath at /Game/V5Signs/Niagara/NS_*), and era-correct biome meshes those catalogs name are described, not baked. Where a claim depends on that art, this page says so.

"Cell" means a mechanic stack composed by thin variant modules. As in the Urban-Crime cell, the frame-critical verbs live in the four shared cores, and the playable surfaces are composition modules whose Build.cs wires the mechanics they need: V5HunterWitchersPath.Build.cs pulls in V5Alchemy, V5Signs, V5MonsterHunt, V5Melee, and V5Squad; V5HunterContractBoard.Build.cs pulls in V5HunterWitchersPath, V5Investigation, and V5MonsterHunt. The honest consequence is that the variant modules are heavier on catalog assembly and shape-gating over large authored datasets than on novel per-frame algorithms — those live one layer down. And one boundary matters throughout: the core systems ship as UBlueprintFunctionLibrary verbs that compute outcomes (toxicity, pelt grade, sign cost, trail weights); the in-world campaign actors apply those outcomes to health, inventory, and the world. The libraries are the honest seam between math and play, and the sections below keep that distinct.

The monster-hunter experience — what the cell plays like#

Strip the satellites away and the spine is one long campaign that fuses the whole stack. V5HunterWitchersPath is the Witcher-3 surface, and its catalog — validated in V5/ue/Source/V5HunterWitchersPath/Private/V5HunterWitchersPathSystems.cpp — is a content spine with teeth. The builder authors 130 missions (a MainQuestCount = 70 plus a ContractQuestCount = 60) across four regions (EV5HWPRegion: Coastal Duchy, Northern Wildlands, Eastern Marsh, Mountain Freehold) whose areas the spec sums and demands total exactly 155.0 km² (FMath::IsNearlyEqual(…, 155.0f, 0.01f)), with 5 endings, 16 hunter companions, and 120 alchemy loadouts surfaced — every count pinned in V5HunterWitchersPathTests.cpp (TestEqual("Campaign has 130 missions", …, 130)). The protagonist is a mutated, poison-resistant monster hunter; the IP-clean final name lives in the §82 substitution manifest, and this page uses "Witcher's Path" only as inspiration shorthand, the same posture the product takes with "Witcher Sense" and "Wanted Stars."

The campaign is where the stack's interlock becomes visible. Bestiary knowledge gates contracts: a contract-availability escalator demands rising bestiary completion as the campaign deepens — 25 % for early contracts, 40 % past index 20, 70 % past index 45 — so you cannot brute-force a late drowner contract you have never studied. The long-tail narrative is real too: a dialogue ripple system schedules choices to pay off in a 10-to-20-hour downstream window (Ripple.EarliestPayoffHour >= 10, LatestPayoffHour <= 20), each ripple touching ≥ 3 later missions. A Year-1 expansion authors a school-trial arc — 4 ritual missions, 15 new bestiary monsters, a Manticore school variant with a ≥ 10 % toxicity-resistance bonus, and a TrialMaxSafeToxicity gate of 85 % that ties the marquee endgame back to the alchemy ceiling below. All of this is authored-catalog depth with id-drift guards; the playable geometry and montages behind it are described, not cooked.

The hunting, alchemy & crafting systems#

This is the cell's beating heart, and the four cores are genuinely domain-specific code rather than renamed CRUD. The diagram below is the interlock; the subsections walk each core in turn.

Alchemy — a real consumable economy with a toxicity ceiling#

V5Alchemy models the full brew loop, not a crafting menu. The catalog is 120 recipes (30 each of Potion/Oil/Bomb/Decoction, the EV5AlchemyRecipeType enum) drawing on 180 ingredients (60 herbs, 60 mushrooms, 60 monster parts), each recipe consuming exactly three — and the JSON loader (V5AlchemyRecipe.cpp) enforces all of it: schemaVersion == 1, no duplicate ids, exactly three ingredients per recipe, every ingredient reference resolvable, a brew duration in the 5-to-60-minute band, at least one effect, and ValidateCounts refusing anything but the 120/30/30/30/30 and 180/60/60/60 shape.

The load-bearing runtime is UV5_Alchemy_ToxicitySystem::ApplyConsumableToxicity (V5/ue/Source/V5Alchemy/Private/V5AlchemySystems.cpp). It scales a recipe's ToxicityPercent by a resistance scalar (1.0f - Clamp(resistance, 0, 90)/100, so resistance can never exceed 90 %), accumulates it toward MaxToxicityPercent, and once the bar crosses the ToxicityDamageThresholdPercent = 70.0f constant it starts hurting you: SelfDamage = (Current − 70) × 0.5, accumulated across doses into AccumulatedSelfDamage. That single threshold is the Witcher "don't chug five decoctions" rule expressed as interpolation math, and the spec proves it against values, not flags: a first decoction stays under the line (TestFalse("First decoction can remain under self-damage threshold", …)), a second stacks past 70 and trips self-damage (TestTrue("Stacking past 70 percent triggers self-damage", …)), and the damage accumulates. Around it sit UV5_Alchemy_Inventory::GetSlotCapacity (typed slot caps — 5 potions, 2 oils, 2 bombs, 1 decoction — so high-toxicity decoctions are deliberately scarce), AV5_Alchemy_BrewingStation::BrewRecipe (real ingredient-count validation and consumption against a BrewRequest, returning a typed FailureReason on a missing ingredient), and UV5_Alchemy_RespawnSchedule, which gates foraged nodes behind a RespawnCadenceDays = 4.0f cooldown so over-harvesting a biome actually depletes it (TestEqual("Respawn cadence is four days", …, 4.0f)).

Signs — five GAS verbs gated on a shared stamina pool#

V5Signs carries the five elemental casts (EV5SignType: FireCone/ForceWave/Shield/TrapGlyph/MindSuggest — the renamed Igni/Aard/Quen/Yrden/Axii), each with a Base and Charged variant and a five-tier upgrade tree. The catalog (V5SignCatalog.cpp) builds them procedurally: 5 sign families → 10 variants → 25 upgrade nodes → 10 Niagara paths, each node deriving DamageMultiplier = 1 + 0.12 × Tier and CostReductionPercent = 3 × Tier. The interesting code is UV5_Sign_StaminaGate::EvaluateSignCastFromCombatAttributes, which is explicitly wired to the shared combat attribute set: it reads GetStamina() / GetMaxStamina() off UV5_AttributeSet_Combat rather than carrying its own pool, so signs draw from the same stamina that dodge and parry regenerate. The gate applies the upgrade node's cost reduction (clamped to 80 %), scales EffectMagnitude by the node's multiplier, and enforces that a bRequiresFullStamina charged cast needs ≥ 95 % of max (FullStaminaThreshold = MaxStamina × 0.95) — failing loud with a typed FailureReason rather than silently succeeding. V5Signs.Build.cs links GameplayAbilities directly, so each sign is a real UV5_Ability_Sign_* over the GAS spine, and the spec confirms each ability derives from UV5_Ability_Sign_Base and reports MatchesCell(EV5Cell::Hunter).

Bestiary & Witcher-Sense — the investigate-then-fight loop#

V5MonsterHunt is where the cell's hunting fantasy lives. The bestiary is 80 entries across 12 categories (EV5MonsterCategory: Specter/Vampire/Drowner/Necrophage/Hybrid/Ogre/Dragon/Golem/Undead/CursedOne/Doppler/Elemental), each carrying WeakVsOil / WeakVsSign / WeakVsBomb tags that close the loop back to alchemy and signs. UV5_MonsterHunt_WitcherSense::SetSenseEnabled drops camera saturation to 0.45 and lights up six clue colours (amber scent, crimson blood, ochre track, green foliage, blue sound, violet magic); BuildHighlightedClues filters to clues within range and sorts them by proximity, and UV5_MonsterHunt_TrailFollowing::BuildTrailFromClues turns the sorted clues into nav markers weighted 1 / max(1, distance) so the trail naturally pulls toward the nearest sign (TestTrue("Trail nav weights prefer closer clues", …)). Bestiary completion is a real monotonic state machine: ApplyUnlock advances a monster from Tome (25 %) → Encounter (40 %) → CombatStudy (70 %) → Defeat (100 %), taking the running max so a scholar tome bought early can pre-fill knowledge, and at 100 % UV5_MonsterHunt_DamageBonus::GetDamageMultiplier returns a 1.2× bonus — knowledge literally becomes damage, and the spec pins both the 1.0 below 100 % and the 1.2 at completion. The contract scheduler (UV5_MonsterHunt_ContractPostingScheduler) posts on a 36-hour cadence and expires entries after ContractExpirationHours = 168.0f (seven in-game days), verified by a spec that posts at hour 72 and asserts expiry at 240; scholar tomes cost 80 in-game currency.

Hunting — perfect-pelt scoring and trapper crafting#

V5Hunting is the frontier/hunter foraging economy that the cell shares with the Frontier cell (65 species, 60 trapper outfit recipes, all three pelt grades authored). UV5_Hunting_PerfectPeltScoring::ScorePelt encodes the RDR2-style cleanliness rule precisely: a Perfect pelt requires the correct caliber for the species and a clean kill (ShotCount == 1 to head or vital) and field-dressing within PerfectFieldDressMinutes = 15.0f — miss any one and you drop to Good or Poor with a typed reason, each downgrade path value-checked (wrong caliber → Poor, late dressing → Good, body shot → Good). UV5_Hunting_AnimalAI::EvaluateAnimalStimulus resolves prey behaviour by strict priority — a nearby predator forces Fleeing at 1.2× flee speed, then line-of-sight inside SightRangeMeters flees, then sound inside HearingRangeMeters only Alerts (so a snapped twig does not always spook the deer) — and UV5_Hunting_TrackingMode is the frontier "Eagle Eye" cousin of Witcher-Sense (saturation 0.52, amber accent, proximity-sorted signs). The crafting payoff is UV5_Hunting_TrapperProgression::EvaluateRecipeUnlock, which counts how many of a recipe's required species you have delivered as matching perfect pelts and unlocks an outfit only when both the perfect-pelt count and the dollar cost are met — over-harvesting the wrong animal does not help. CarcassTransport enforces the one-rear-slot horse constraint and refuses CatchOnly species, the same physical honesty the rest of the cell applies to its economies.

The contract economy and the procedural surfaces#

Around the campaign sit three satellite modules that reuse the cores. Each is a composition module — heavier on validated catalogs than on new per-frame math — but each carries at least one real runtime algorithm, and all three are compiled and value-tested.

Contract boards — the quest delivery surface#

V5HunterContractBoard is the town-board layer over the V5MonsterHunt scheduler. Its catalog authors 24 contract boards (validated as exactly 6 per region across the four regions), 60 contract templates, and an 8-stage contract flow (ReadBoard → Alderman → Investigate → Identify → Prepare → Fight → Proof → Reward) — the full Witcher contract ritual encoded as a state sequence. Posted contracts inherit the core's 36/168-hour cadence (TestEqual("Posted contracts expire after seven days", …, 204.0f) — a contract posted at hour 36 expiring at 36 + 168), expired rows dim their opacity below 1.0, and because the module depends on V5Investigation, each contract's investigation phase pushes into the shared evidence/Mind-Palace surface the period cell shares.

The card minigame — a self-contained collectible game#

V5HunterCardGame is the gwent-equivalent, and notably its Build.cs depends on only V5CardGame — it is a pure content-and-rules composition over the shared card engine. Its ValidateModeCatalog pins 320 cards across 5 factions at 64 each (GroveWardens, AshenCourt, Tidebound, IronVow, StarfallCircle), 4 in-fiction tournaments (each seeding the player plus three opponents), 5 merchant side missions, a 25-card starter deck, and a 2-player PvP mode that runs on an bUsesAuthoritativeActionHash flag — the same anti-cheat posture the online surfaces use. The tournament resolver runs a real best-of bracket to a single champion, and a side-mission progress evaluator tracks wins-remaining and gates rare-card rewards behind merchant-lead purchases.

Roguelike Hunter Run — permadeath over the procgen core#

V5RoguelikeHunterRun composes V5Procgen and V5OnlineServices into a permadeath run, and it carries the cell's most algorithmic satellite. The catalog authors 24 procedural map templates and 20 Year-1 run modifiers (alchemy-limited, signs-disabled, toxicity-surge, armor-shattered…), each with its own loot/toxicity/enemy multipliers and a leaderboard score bonus. Run generation is deterministic and seeded — two runs from the same seed produce an identical StableFingerprint — and lays out 5 branching steps with a boss as the final step. Death is final: the lifecycle machine resolves to FailedPermadeath, ends the run, and increments DeathCount. The score is a genuine formula — BaseScore = CompletedSteps × 1000 + RewardCrowns / 5 − ElapsedSeconds / 2, then scaled by (1 + ModifierScoreBonusPercent / 100) and floored at zero — and a run is only leaderboard-eligible when it completed cleanly and passed anti-cheat, with the per-run leaderboard scoped to the seed so runs are only compared against the same generated dungeon.

Where this connects#

The monster-hunter cell is one face of a single game, and it hands off at well-defined seams:

• The shared foraging economy. V5Hunting — perfect pelts, prey AI, trapper outfits — is the same core the cowboy cell hunts with; the Frontier cell spends it on Dead Eye and bounty rather than monster contracts. See ./frontier-cell.md.
• The other systems-first cell. The Sci-Fi squad cell is the cell most like this one in spirit — a deep, loadout-driven preparation loop — but spends it on squad command and hard-vacuum tactics rather than alchemy. See ./scifi-galactic-squad.md.
• The cross-cell spine. The wanted curve (era-scaled to village watch and lord's guard for this cell), the honor bridge (the hunter's WitcherHumanity feeding the cross-cell moral compass), and the Bureau-XP ledger every cell sits on are shared with the crime cell — see ./urban-crime-cell.md.
• Architecture companion. The alchemy/toxicity, sign-stamina, bestiary, and hunting verbs — in prose with line citations, alongside the period-drama and Bureau systems — live in ../architecture/hunter-period-systems-and-bureau-spine.md.
• The feature hub: ../V5_features.md.