[2] For Fantasy Flight developed material, the Warhammer 40,000 Roleplay system is explained and used with small differences in a series of five independently playable games.
Each has a different, narrow focus and multiple supporting books of its own: When the Warhammer 40,000 Roleplay license was transitioned to Ulisses, the system was re-designed.
The first campaign under the new developer is Wrath & Glory, which allows player characters of many different races and backgrounds, and implements a card deck system that is used alongside traditional dice rolling.
The game allows for many other missions, including wiping out dangerous gangs, gathering evidence of corruption, dealing with alien threats or eliminating rogue psykers.
These individuals are recruited from their native Chapters (fighting units of approximately 1,000 people) to serve as a military arm of the Inquisition, against particularly dangerous heretics known as Chaos worshipers and alien lifeforms known as Xenos.
[6] In Only War, each player takes the role of an Imperial Guardsman, one of the billions of hardened conscripts constantly fighting on myriad fronts at the whim of the Earth-based government of the Imperium (Adeptus Terra).
Game mechanics also introduce a wide variety of special rules that provide bonuses and reductions in certain areas (For example, a character from a hive world has a higher Fellowship, but a lower Toughness.)
In Dark Heresy, each player picks a career path for their character, which is similar to a class from other RPG systems such as Dungeons & Dragons.
To advance in their career path, a player character earns experience points (XP) and spends them to gain skills and talents or improve their characteristics.
[12] During late 2008 and 2009, Fantasy Flight started releasing autonomously-developed material for the Dark Heresy game: a collection of heretical factions to pit the player characters against titled Disciples of the Dark Gods, a monster manual called Creatures Anathema, and a mini-campaign in three parts dubbed The Haarlock Legacy.
Fantasy Flight also announced a manual on "radical" inquisitors (covering the most extreme factions, their tactics, equipment, and most prominent figures) and a major expansion allowing players to take their characters to the rank of interrogator, bestowed with an inquisitorial rosette, enjoying augmented prestige and able to summon more powerful allies.