Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
Mordheim: City of the Damned is based on the Mordheim tabletop game, which was a skirmish-oriented derivative of the larger Warhammer Fantasy wargames. Accordingly, the video game puts the player in control of a small warband that fights rival teams over resources and control of areas around the titular city of Mordheim. At the start of the game, the player chooses a faction (Sisters of Sigmar, Mercenaries from the Empire, Skaven, or the Cult of the Possessed) and over the course of the game, is given to opportunity to improve their warband's strength by recruiting, leveling, improving and customizing a roster of combatants as well as their equipment. Losing battles can lead to permanent death of the members of the player's warband, and the game emphasizes careful engagements and survival.
In addition to a single-player campaign, players can pit their warbands against other players online.