Why are there different types of Terrain?

The main purpose of different types of Terrain is to create more possibilities for individual combat strategies and diversity in battles. The game offers different climate zones (forest, snow, and desert areas), which provide basically the same battle terrain options in a different look. The only difference is Brigand Island that offers unique terrain and objects.

Common Terrian Tiles

These are the basic tiles that have no advantage or penalty. They come in a variety of formats (e.g. grass, snow, desert, roads, bushes) that all have no gameplay effect. Only the Free Knights have a Passive Ability, called Master of Plains that will increase the damage by 20% when attacking a non-Pike regiment on plains.

Forest tiles absorb 50% of damage taken by the regiment hiding there. This means that the unit will only take half of the damage that is dealt to it (including Critical Hit damage).

When entering a swamp, your movement immediately stops. While in a swamp, all damage taken is increased by 50%.

The bridge tile can cross regiments over a river. Additionally, a regiment can use it as a strategic point to protect against melee attacks from the sides when staying on a bridge. Melee attacks can only be issued from regiments situated at the entrance and exit of a bridge. This protection does not apply for special melee abilities such as Furious Whirlwind utilized by Toom-Pah’s Bunch as it will hit any adjacent hex.

Regiments located on a hill tile have their damage output increased by 50% if their target is on a lower plane on the battlefield. Sometimes hills also have a rocky border that protects any regiment on that tile from melee attacks adjacent to those cliffs.

Blocker Tiles

Rocks cannot be entered or passed except by flying regiments such as Maiden's Faeries.

Water cannot be entered and only crossed by way of bridges. Maiden's Faeries can fly over water.

Special Tiles

Regiments staying at a village will recover 20% of their max HP at the beginning of their turn. This will add to other effects such as the passive healing ability provided by the Tree of Healing. The maximum healing you can get is 50% HP recovery per turn.

Ancient Tower
Ranged regiments located at an Ancient Tower can benefit from its effect and add 1 hex to their total attack range. This means that an Archer regiment with a range of 3 will get their range increased to 4 instead.
An Ancient Tower will not modify the range of spells and abilities, however. That means you will not be able to cast Rain of Fire at a range of 4 while on an Ancient Tower, for instance.

Ancient Towers are also considered as an elevated terrain type which translated into a 50% damage bonus if target is on a lower plane of the battlefield. They can also only be accessed from its entrance which also limits melee attacks to one adjacent field.

Loot Wagon
During Raiding Brigand battles you will encounter a special tile that has a Golden Chest on it. If you collect it before the fight ends, you will receive a special bonus for the regiment that collected the loot, for example Shards or an unapplied Upgrade (if all upgrades are applied you can get a random upgrade instead).

Mortars are defensive artillery set up on Brigand Island to fend off intruders. They shoot a projectile every 2 turns which explodes on impact hitting 6 tiles 2 hexes away with shrapnel. On turn 1 of a Brigand Island battle all mortars load. Every other turn they will fire on an enemy regiment. Shrapnel can hit regiments 2 hexes away from the zone of impact, so regiments adjacent to the initial target are safe. Mortars have no range limitation.

Barrels are filled with explosives and can only be found on Brigand Island. When destroyed, they deal damage all around it. Attacking this tile will immediately destroy it. Barrels cannot be surpassed except by flying regiments.
Any damage effect (e.g Rain of Fire, Whirlwind, Lightning Nova) will destroy barrels, so destroying a this with other barrels adjacent to it will create a chain effect.

Burning Tiles
Burning hexes appear when the Rain of Fire ability has been used. For a few turns these hexes will be on fire dealing damage and ending any movement when entered. Furthermore, regiments on burning tiles will receive 25% damage of the regiment's base damage which has caused this effect.