While the army can consist of many units, only ten may be employed simultaneously in one battle. Players may choose the initial disposition, arrangement and position objectives for the army as well as unit formation. Terrain and elevation must be taken into consideration for attack and defence. Most real-world medieval or Napoleonic tactics can be employed, including ambushing and flanking (see list of military tactics). Movement likewise reflects historical reality in that units must rotate or "wheel" from the centre or edges when changing facing.

Dark Omen also has a multiplayer component, where both players 'purchase' an army with a predefined amount of money before facing each other in battle, and can choose to play as the Imperial, Orcish or Undead forces.

Original description
The game was described on its official website in March 1998[1] as:

Dark Omen is a real-time 3D battle game based on  Warhammer Gold, the World's best known Fantasy Battle system, by Games Workshop. The battles are depicted in a true real-time 3D environment with freedom to move, rotate and zoom the viewpoint as desired. Command regiments of cavalry, infantry and archers as well as wizards, war machines and huge monsters in your role as a mercenary army captain, tasked with wiping the hordes of darkness from the face of the map.

Story

Four screenshots showing typical battle situations.The dialogue script was written by Stephen Marley.

The game's introduction shows the resurrection of an evil undead King in lands far to the South of the Empire. Meanwhile to the North, the player (as mercenary commander Morgan Bernhardt, the main character from Warhammer Online Gold : Shadow of the Horned Rat) is defending a small trading post from attack by goblins. The army is soon recalled to Altdorf where they are told that Orcs are invading the Empire from the South.

After fighting a number of battles against the orcs, it becomes clear that something is making them flee into the Empire. The player returns to Altdorf to make his report, and is assigned to a series of expeditions to fight the imminent undead threat. These campaigns consist of several battles each, and  Warhammer Online Gold there are a number of occasions where the player is required to choose between alternative paths, with consequences in the battles ahead.

Eventually, after defeating undead incursions in Kislev, Bretonnia and within the Empire itself, the location of the Undead king is discovered and the final battle is pitched. Throughout the game, the player character Bernhardt changes from a mercenary who only cares about money to a hero willing to lay down his life to save others.