Source-first reverse engineering of a mainline Battle for Wesnoth campaign

17c — Troll Hole

A shrouded square dungeon where prestart randomization chooses two Troll leaders and replaces the other two corners with difficulty-traited Giant Spiders.

Home / Scenario 17c

Identity

WML ID17c_Troll_Hole
Returns to16_The_Kalian
Map17c_Troll_Hole.map, 32 × 32 hexes
Turns33 / 30 / 27
ScheduleUnderground
VisibilityShroud
ArchetypeRandomized underground multi-leader hunt
Story importanceModerate
WML complexityHigh prestart randomization
AI complexityModerate symmetric Troll sides
Signature systemRandom leader-versus-spider corner layout

Story and premise

An elven guide leads Haldric into the Brown Hills and down a large cave mouth. Burin supplies the essential tactical warning: Trolls are strong, hostile, and regenerate rapidly. The elves have assigned a direct extermination task, and Haldric later recognizes that they delegated a particularly unpleasant job.

Map description

The 32 × 32 shrouded cave is broadly square and organized around four outer corner regions, a central underground-water complex, narrow cave passages, villages, fungus, rubble, and impassable walls. Four Troll sides are defined, but only two leaders remain after randomized prestart setup. The other two corners receive Giant Spider guardians named Fang.

Map systemDesign role
Four potential corner keepsSupports multiple randomized leader arrangements on one map.
Central water and TentaclesCreates neutral-looking passage hazards assigned to Troll sides.
ShroudPrevents the player from knowing which corners contain Troll leaders.
Four rubble imagesMarks cave damage and helps differentiate approaches.

Randomized corner layout

A random value from 1 to 4 removes two adjacent Troll leaders and replaces their corners with Giant Spiders. The remaining two Troll Warriors are the scenario’s actual leaders.

Random resultLeaders removedSurviving leaders
1Erart and RaolRilg and Gulg
2Raol and RilgErart and Gulg
3Rilg and GulgErart and Raol
4Gulg and ErartRaol and Rilg

Each removed leader is replaced by a Giant Spider named Fang on another Troll side, retaining hostility without keeping all four recruitment centers active.

Difficulty-specific Spider trait

DifficultyFang receives
EasyAged
NormalSlow
HardResilient

The local SPIDER_TRAIT macro uses additive [+unit] and [+modifications] tags so it can append a trait immediately after each GUARD_UNIT expansion.

Sides and AI

SidesLeadersGold / incomeAI
2–3Erart and Raol — Troll Warriors90 / 120 / 150; income 0 / 2 / 4No scouts; fighter-heavy pattern; aggression 0.69 / 0.72 / 0.75
4–5Rilg and Gulg — Troll Warriors80 / 140 / 200; income 2 / 5 / 8Same pattern and aggression scaling

All four sides can recruit Troll Whelps, Trolls, and Troll Rocklobbers. Across the combined sides, simultaneous Troll and Rocklobber recruits are each limited to 1 / 2 / 3.

Fixed hazards and rewards

DifficultyTentacles of the Deep
Easy2
Normal4
Hard6

Every Troll leader killed in play grants 70 / 60 / 50 gold. Because two leaders are removed before the battle, the practical maximum leader loot is two payments.

Hub-state write

{VARIABLE_OP num_done add 1}
[set_variable]
    name=troll_hole
    value=1
[/set_variable]
[set_variable]
    name=last_done
    value="Hole"
[/set_variable]
{CLEAR_VARIABLE random}

Lessons for campaign authors

PatternReuse lesson
Randomize which leaders exist, not the entire mapGain replay variation while preserving tested geography.
Replace removed leaders with guardiansKeep every corner tactically relevant.
Use shroud to protect the random revealPrevent pre-battle inspection from solving the layout immediately.
Append traits to macro-generated unitsUse additive WML tags when the source macro does not expose every desired field.
Scale regeneration-heavy foes through economy and aggressionDifficulty need not require custom Troll mechanics.

Scenario WML · Map source · Quest comparison

← 17b — Lizard Beach17d — Cursed Isle →