Battle Brothers, first released as an early access title on Steam and debuting as a full game in March 2017 is a mix of rogue-like, turn-based tactics and RPG set on the randomly generated map in a medieval setting slightly resembling central Europe (namely - Germany) of XII and XIV centuries with low-fantasy elements: Orcs, the Undead, and necromancy.
With its emphasis on "anyone can die" and bleakness of the world, the overall atmosphere of the game is heavily inspired by Black Company fantasy series of novels, Myth games, and Darklands.
The game does not rely on any concrete plot. The player becomes a leader of a mercenary company decimated in a recent skirmish and what comes next is all up to the new captain, who has to rebuild the strength of the warband - replace lost men, redeem lost renown and gain fame in harsh world where brigands and wild beasts wait for unprepared travellers, an army of undead slowly rises somewhere on the edge of the map, Orc bands grow stronger each day and there is a looming shadow of war between the existing human factions.
The player can decide what end-game crisis will be the final challenge - aforementioned undead scourge, Orc invasion or all-out war between humans (it can also be randomized). But only the best players will reach this stage of the game, even on the easiest difficulty (and there are three levels both for economic handicaps and for battles), as in most roguelikes, many defeats and restarts are needed to learn the mechanics of the game and the challenges it presents.
The player starts each game with three surviving mercenaries who always have a certain build - one spearman (using spear and shield), one two-hander (using woodsman axe) and one ranged (using crosbow), but the game mechanics do not use class system or do not restrict equipment a given soldier can use - what type of weapon and armor each man in the company uses is completely up to the player and is restricted only by the money spent in shops for spears, cleavers, axes, swords, pikes, leather jackets, chainmails, plate armors and other standard medieval tools of the trade. The equipment can be also looted from dead enemies and all weapons and armor are subject to damage which has to be repaired (which takes a certain amount of game time on a world map).
Instead of a stiff class-based system, recruitable mercenaries are described by a set of attributes like health, fatigue, melee and ranged skill etc as well as perks - each level up (due to the experience gain after fights) means the mercenary can level 3 out of 8 skills and choose 1 perk out of 50 (the choice is restricted by the merc's level and the level cap is 11, so the player has to thoroughly think about the build for each soldier - no backsies!).
Each recruitable mercenary also has a background which more or less tells the player what skills will be better developed at the start and what specialization (a skill with up to 3 stars which gains more points after levelling up) the merc can have - hunters have better ranged weapon stats, brawlers usually have more hit points.
Every merc can also have a random, good or bad trait - some are asthmatic (which slows them down in battle), some are brave (have better resolve, ie. better morale checks) and so on. They can also gain permanent wounds after really hard battle which cripple them and make them less useful during combat (the player can retire any mercenary at any time).
Each new game starts on a randomly generated map of a medieval world consisting of a dozen villages and cities belonging to different factions (which can be befriended or antagonized through finishing or failing tasks for each of them or by attacking their units on the map). Each location has its own set of buildings aiding the player (for a fee, of course), in accordance with a nearby feature - a town with an iron deposit has a huge chance to have a weaponsmith or armorer selling better equipment, a castle usually offers a training ground and a better selection of mercenaries to hire, while a big city has a well-equpped marketplace and a temple where the soldiers can be healed.
During the voyages on the world map (which take an in-game time that can be sped up) the player can encounter non-hostile mercenary groups, caravans, and garrisons as well as hostile beasts, bandits, zombies, orc and goblin raiding parties or enemy camps.
After encountering an enemy on the world map, the game changes its perspective to an isometric view of a battlefield which is a hex grid. The battle map is dotted with hills (high ground is obviously important for ranged characters) and different obstacles which decrease movement range and accuracy as well as drain fatigue from the soldiers on both sides.
Battles are turn-based with initiative attribute (which can be decreased by weight of equipped items and wounds suffered) deciding the order of movement and attack for every character on the map. The battle is won when every enemy is dead or broken (in the latter case the battle can be continued to butcher the running foe) and the player can retreat any time, although any merc who was gravely wounded dies in that case, while others suffer heavy injuries that take a couple of in-game days to heal.
During battle mercenaries (and foes) use a selection of different skills depending on the equipment they carry - those who have shields can muster a shield wall which boosts their defenses, those with axes can try to destroy the enemy's shields, while those with swords can attempt to parry attacks. The results of each action are decided by a dice roll modified by a relevant attribute and held equipment.