Battle for Middle Earth 2 - Good Campaign - Mission 7 - Erebor

Battle for Middle Earth II - Good Campaign Mission 7 - Erebor
This is a hint/walkthrough post for Battle for Middle Earth II. You can find an index of all our Battle for Middle Earth II posts here.

This is a hectic, almost non-stop mission that happens in six attack waves. In between waves, you have only a certain amount of time to destroy all enemy troops because the appearance of the next wave is timed, and not triggered by whether you've completely destroyed an enemy wave or not.
If you don't have at least Bombard or Cloudbreak (preferably both), this mission can be very difficult.

Wave 1 - Corsairs.

Wave 2 - Corsairs who use firebombs. Handle the one Attack Troll first.

Wave 3 - Some Haradrim archers and two Mumakil who go straight for buildings and therefore can just be chased with archers.

Wave 4 - Mordor Invasion Wave 1

• Orc warriors and Archers, and a few Battering Rams. If they split up going in between buildings in the city, this entire wave can be handled by the initial troops you are provided. Otherwise, they will probably go for the western passage as it is closer.
• The lone Black Rider scouts ahead alone and can be taken down by your troops, but support them with King Dain. At the end of this wave, some trolls enter from the eastern passage.

Wave 5 - Mordor Invasion Wave 2

• At the start, the enemy launches an Arrow Volley (the power) at King Dain. Separate him from the main group of dwarven units.
• A lot of Mumakil and Corsairs (who can go over walls) start from the south. A large additional group of Corsairs arrives from the western passage a little later, usually once your western fortress comes under attack. Once most of the Mumakil are stalled at the ramp up and bunched together in range of your Fortress catapults, CloudBreak can be a great power to use to stall them while your Fortress catapults continue raining exploding shots.
• You may not want to use your powers right away. Notice in the video that during initial Mumakil and Corsair attack, when the Corsairs are on the wall the Mumakil also rams the wall. Since there's no protection from friendly fire, the Mumakil killed the entire lot of densely packed Corsairs.
• A small force of orc builders will try to establish a fortress and some buildings around the lower middle part of the map. The Mordor Fortress will mostly be passive initially but they are building Siegeworks and Troll Pens, so you will want to clear it out as soon as possible. If you go after them, you will end up splitting the attack wave, but the Corsairs are probably better handled at your western fortress where you can bunch them up and bombard them with your Bombard power and your Fortress catapults. Besides, if you do not stop them there, most will just rush past your fortress and into the dwarven stronghold area.

Wave 6 - Mordor Invasion Wave 3

• At the start, the enemy launches an Arrow Volley at a Builder.
• This wave is mostly veteran trolls (that can't be killed outright by the Bombard power), and some catapults.
• Elven reinforcements come from the western passage, usually when the fighting is thick there. If you don't control them right away, the catapults will destroy enough of them to render them largely useless.
• Most trolls stop to fight, but a small force beelines for the throne for an automatic victory if they destroy it.
• A small force enters from the eastern side of the dwarf mines, through a small side door. If you've got nothing there at the time, intercept them with forces you can build from the buildings there.

Restart this mission a few times initially to get the lay of the land--There are limitations on where you can build towers and fortresses. Also, you will want an idea of how much you can build on initial resources. It's easy to spread too thin by trying to fortify all three entrances early.
In general, you will need one Fortress at the western and eastern entrances, and one probably right in front of the throne, although this one can generally wait. You can build and fortify that one later. You will probably find you need a Fortress Build Point to get a Wall Hub before you can put down any walls. Before then, wall hubs will be in blue -- a legal position, but you are presently barred from building it there.

Fortresses should be upgraded with at least Dwarven Stonework and Masterwork Munitions at a minimum. If you build the western fortress closer to the ramp up, and shut the main gate to your throne room, you can generally attract the full attention of the Mordor invasion waves and funnel them tightly on that ramp before using the Bombard power to help you clear it. Also, Masterwork Munitions will add a big fire splash to your Fortress catapult towers, for a lot more damage in that tight space--Multiple battalions of Corsairs can be instantly killed with a single volley!

Before the start of the second wave, you should have a fully upgraded fortress in front of your throne room, and some walls. Encase the throne, but be careful of blocking the movement of your own troops around the throne and Fortress as Wave 6 comes at you from all sides. If you find yourself stuck, demolish a section of wall to rush your troops over to where they are needed. Keep an eye on the Nazgul mounted on Fell Beasts (you can watch them from the Palantir as hollow red circles) and intercept them with your archers or axe throwers.
Once the fighting gets hectic, especially in Wave 6, you will probably not have time to micromanage building anymore. Instead, just go to the nearest building where you can recruit troops and use Shift-click to queue 5 battalions at a time.

Something useful to do is to build a Hearth near a Mine far from the front so that you can, between missions, get your troops there for healing. Also, a Mine at the west and east passages can also help a lot.

Trolls are very dangerous to the Fortress towers -- one stone lob can take down a tower on a Build Point instantly. They do less well against actual walls, so you will want to shield your Fortress with walls as far ahead as possible, but not so far that your Fortress can't fire catapults to land in front of the wall. If you can manage it, having an inner wall can further slow down the enemy.
Walls alone cannot hold the Mordor forces because Corsairs can climb over. Moving your troops over to support them during Wave 2 is vital.