Terrain (Japanese: 地形効果 terrain effect) is a mechanic which influences how units interact with and are affected by the terrain of the world around them as they progress through battles. Different types of terrain can impair how far a unit can move across the battlefield in a single turn, but conversely hiding in rougher terrain also helps units better defend themselves from enemy attack.
Every space/tile on a chapter's map is classified as a type of terrain, and accordingly brings with it a set of properties which influence the stats of a unit who stands on or passes across it in several ways. The default terrain type is plains (or floor when indoors), which is a neutral terrain with no effect on units' stats and allows them to move unhindered. Other recurring terrain types include:
- Forest or Woods: A forest covered tile which hinders movement through it, but in exchange the trees grant a unit defensive cover. In indoor maps, Pillars perform a similar role.
- Mountain: Hilly terrain which can be crossed by infantry units, but hinder movement even more than forests; they also give defensive cover. Horse-mounted units cannot cross mountains at all.
- Peak: Large, towering mountains which cannot be crossed by the majority of units who fight on the ground. Only flying units and Brigands can cross peaks.
- Water: Bodies of water can only be crossed by a handful of infantry classes, although very slowly and often only one tile per turn. Pirates have a much easier time crossing water, and flying units are again able to cross
- Fort: These small defensive fortresses can protect a single unit, boosting their defensives and healing them slightly at the start of every turn.
- Wall: Solid stone walls which cannot be crossed at all, except by flying units (and even then, sometimes they are disallowed). Usually they can only be crossed by unlocking doors or breaking cracked sections to clear a path. In outdoor maps, thickets - particularly thick forest tiles - perform a similar role and also cannot be crossed.
- Stairs: This terrain type, which only appears indoors, offers no bonuses but is notable as frequently being points where reinforcements appear.
The primary effect terrain holds on gameplay is the concept of movement cost or terrain penalty, the effect it holds over a unit's movement range. The movement cost value, associated directly with the terrain type, determines how many movement points held by a unit are consumed when attempting to cross a tile. The standard cost for basic plains terrain is 1 movement point per tile, and thus has no tangible penalty. Other terrain types such as forests have a higher movement cost, typically requiring 2 movement per forest tile crossed, and thus limit the unit's movement distance should they be moved in that direction.
- For example (pictured): Lewyn possesses 6 movement. On normal plains terrain, this allows him to move a maximum of six tiles away from his starting point, at a cost of one movement per plains tile (pictured: his movement range to his left). However, were he to cross through two forest tiles, he would only be able to move a maximum of four tiles as each forest tile has a cost of two movement per tile (pictured: his downward movement range).
Different classes typically have different movement costs depending on the terrain. Typically, horse-mounted units like Cavaliers and Troubadours are penalized more for crossing forests and are incapable of crossing mountains at all, flying units like Pegasus Knights and Wyvern Riders are not hindered at all by terrain penalties, and non-mounted magic units are significantly less affected by the severe movement cost of desert terrain.
Unique to Genealogy of the Holy War is the road terrain, the only terrain which gives an inverted movement "cost": for all non-flying units, the terrain cost for roads is 0.7 movement per tile, boosting their movement by a factor of less than 1.5 while traversing roads. With the assistance of an unbroken stretch of road terrain, a unit's movement can be boosted by between 2 or 3 tiles.
Stat boosts and reductions
Acting as compensation for the movement impairment, various terrain types offer temporary, minor bonuses to a unit while they stand on the terrain. These typically come in the form of stat increases to avoid and defense, and less frequently, resistance; this encourages players to have their units end their turns under the cover of defense-boosting terrain, and is a valuable asset to units with inherently low defenses. The most common forms of defense-aiding terrain are forests, mountains and forts.
Less commonly, certain terrain types will heal a small amount of HP to units who stand on them at the beginning of their turn, often in addition to defensive boosts. The most frequent form of terrain to do this is forts, with most chapter maps having several forts scattered across them. Gates and thrones, the goals of seize-objective chapters, also restore HP to their occupier, adding to the challenge of defeating the bosses situated on top of them. Some other games have their own unique HP-restoring terrain, such as the healhedges of the Tellius duology and the castles of Genealogy of the Holy War.
Fire Emblem: Radiant Dawn is the only Fire Emblem game which takes varying heights of different parts of the map into account, giving further boosts and penalties against units depending on their level of elevation; this mechanic tends to be common in other strategy RPGs, but is absent from Fire Emblem outside of Radiant Dawn. When a unit attacks their foe from a higher elevation on the map, their damage output, hit rate and avoid are all boosted, while their foe's hit rate and avoid are lowered; conversely, attacking a foe who is positioned higher up than the unit will reduce the unit's hit rate and avoid, while their foe benefits from the height advantage. Attacking an enemy on the same plane will award no height bonuses either way.
Terrain stats by game