_Warhammer: Mark of Chaos – Battle March_ is the first add-on for Warhammer:
Mark of Chaos.

Two new races join the eternal fight between the forces of good and evil. One
are the Dark Elves which are ruled by the Witch King. They come from far
beyond the Great Ocean and left their home Naggaroth to pillage and raid among
the other races. But the real goal of the Druchii is to return to the island
of Ulthuan – birthplace of all the elves and current home of the High Elves.
The second new race are the Orcs & Goblins who created a loose alliance under
their stupid and violent leaders to aimlessly raid the other races. In their
war-campaign, called the “Waagh!-Offensive”, they have now entered the heart
of the land and the old races need to defend themselves against these
relentless hordes that only know one thing: War!

During the single player campaign the player takes over the control of the
Empire, the Orcs & Goblins and the Legions of Chaos. But in multiplayer all of
the now six races (Legions of Chaos, The Empire, High Elves, Dark Elves,
Skaven and Orcs & Goblins) are available to fight in the new multiplayer mode
called “World Domination. There the old world is divided into several dozen
territories and the goal is of course to gain control over every one of them.
But this is no game mode that only a few players play. Instead the map is
hosted by the developers and every player can join in the fight. Once a player
chose a race, he can then attack one of the enemy territories which then
activates a normal skirmish battle with different victory conditions. Once a
race has won a hundred battles in that territory, it gains control over it.
Depending on the territory, the race then gains a bonus like a higher gold
production ratio or a 10% increase in fighting moral.

The add-on also includes several new multiplayer maps and a new unit for each
of the original four races.