Battle for Middle Earth 2 - Rise of the Witch-King - Mission 7 - Plague Bearer

Battle for Middle Earth II - Rise of the Witch -King - Mission 7 - Plague Bearer
This is a hint/walkthrough post for Battle for Middle Earth II: Rise of the Witch-King. You can find an index of all our Battle for Middle Earth II posts here.

You do not have to hold all the barrows to corrupt 1000 souls before the time limit. Three or four should be fine. At each barrow, put down 2-3 towers (upgraded to ice arrows if you have the Resources), and garrison your sorcerer inside. A garrisoned sorcerer still counts as being atop the barrow and will still corrupt souls.
Keep building Mills whenever you can.

Build a few more battalions of Dark Rangers so that you can use their Arrow Volley to take out the riders at each barrow who immediately try to flee to get reinforcements.
Shortly after taking each barrow, whether the rider escapes to call reinforcements or not, some Dunedain Rangers will attack the barrow. Protect your sorcerers and builders by temporarily putting them in a tower.

1-2 battalions of Dark Rangers can sometimes shoot at enemy units without provoking them to move. This is probably because they are shooting from that unit's fog of war, and because they can't see the Dark Rangers, they do not move.