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

Battle for Middle Earth II - Evil 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 mission is remarkably like the Withered Heath (Mission 6), only much more hectic at the beginning. We'll examine the various stages in this mission:

Stage 1:
You start this mission with green troops, no resources, and no archers. Siege units (trolls and catapults) are generally useless against troops that are still moving, so they won't help too much against the enemy raids.
If you lose too many units, you might be in trouble because you'll be stuck with these units for a long time, until you get enough resources. Obviously some powers will help, but probably the best move initially is to pull the units back into a support role and use a power to quickly clear enough buildings to trigger the next stage of the mission, where builders and heroes are sent in. You won't have enough money yet, but at least you have heroes to do most of the fighting.
The enemy units cannot pick up treasure chests, so you can take your time with those.
If you have Arrow Volley, you can kill almost all the dwarven Builders and most of the dwarves in the clump just ahead of your starting position. Follow up with Summon Wildmen of Dunland (who accumulate resources when they attack a building) at the position to immediately grab the treasure and fan out to clear buildings quickly and trigger the next stage of the mission. This can net you over 7,000 in Resources quickly, which will jump-start the production of a fortress. Have one battalion of Wildmen (you get four with the Summon power) capture the Outpost.

Stage 2:
You get the Mouth of Sauron, two Dark Riders (one less than on previous missions), and four Builders. Immediately take control of the Builders and stop them from going too far ahead. Put down a Fortress and two Slaughterhouses nearby. There will be a big rush of enemy troops shortly into this Stage of the mission. If you don't have a fortress or a couple of powers, you are in trouble. If you survive it, the urgency to build and reinforce your location in this mission largely ends.

Against dwarven attacks, move all your troops behind the fortress to give supporting fire: Five catapults adding their fire to protect the fortress will do wonders. Decommission the Orc Warriors because they are non-veteran cannon fodder that would be better used as resources.

Now, focus on trying to add more Slaughterhouses, defending them, and getting Resources to finish upgrading your Fortress and to put a fully-upgraded army together. Don't worry if you lose one of your further-out Slaughterhouses. Just try not to let your builders get killed, and definitely don't let your expensive heroes get killed.
For the fortress, have at least one catapult tower and one Watcher (which emits a fear blast) for the outer defenses. You may not need to upgrade your fortress too much as the five catapults you have positioned behind it should help you hold ground against all comers. Have your heroes help, but watch their Health as they can still be affected by your own catapults and fire.
For troops, get Haradrim Archers and upgrade them. Start with a couple of battalions and get them Banner Carriers (from the Orc Pit) to give them more survivability. Have them support your heroes, who should take point in fighting dwarves. Ultimately, fill in your ranks with just one battalion of Easterlings to delay dwarves closing into melee (although your Dark Riders have a Screech that can help in this regard as well), and the rest with Haradrim Archers. You may or may not want Drummer Trolls as they just can't keep up with the rest of your army.
Do not march around with your trolls as they cannot regenerate and will ultimately get killed. Also, their rocks can knock down your own units. Do not march around with your catapults as their area effect fire is liable to kill half your own troops unless you micromanage. Keep these near your fortress, with the catapults behind to safely add firepower.

Stage 3:
Don't miss the announcement about dwarven reinforcements from the southwest -- your starting position. There will be no countdown on the screen, so reposition your forces to expect an attack from the corner. Simultaneous with this assault, Erebor sends reinforcements out, this time with a catapult that, if you don't pay attention, can destroy much of your fortress.
Try to catch Gloin and his dwarven reinforcements just as they are emerging from the corner of the screen, as you can wipe out a lot with strong area-effect powers, or keep them busy with the Mouth of Sauron's Dissent. Summon Dragon is almost worthless here as its breath weapon can't seem to do much against the dwarves in terms of killing them quickly (although against buildings it is very strong).

Stage 4:
After Gloin's reinforcements, the map quiets down a lot. Probably the only attacks will come from the west where Erebor has an entrance with no gate. You can fight your way up and keep them bottled up while you explore the rest of the map. If any of your troops get too close or enter the tunnel there, you will trigger a large push of dwarves. Thereafter, the western wing of Erebor will be emptied out. You can enter to catch the catapults on the mountainside platform from behind. Destroy all the buildings in the side caves, but I do not recommend getting too close to the throne room for now.

Catapults on platforms are annoying to take out from the outside as you are typically required to exchange fire with them. You cannot use your fortress fireball power on them. If you rush a troll in to the base of the platform, you can direct it to throw rocks and the rocks will magically pass through underneath the platform. This is probably an exploit / programming oversight, however.
Instead, after destroying the catapults on the west side, escort your own catapults to the main gate and take out the big axe towers flanking it. Let the main gate close and don't tear it down yet.

At the west side, secure it with several fortresses (maybe five just below the plateau, to cover not just the Erebor west wing entrance but potential reinforcements from off-map coming from the west). Move your forces to the main gate. Plant a fully-upgraded fortress as close to the main gate as possible, then take down the gate (your fortress, especially if it has a catapult tower, can also do this).
King Dain and the last of the dwarves will charge after a short warning. Support your tower with catapults from behind and you should be able to destroy this last assault without using any powers. Erebor should now be empty. Go in, take down the inner wall, and destroy the Throne.

Stage 5:
You can also delay destroying the Throne to clear out the rest of Erebor. From the throne room you can continue on to the east wing, clear the buildings there, and take out the catapults on the eastern mountain face platforms. As you explore the eastern wing and head out of Erebor, there will be two groups of reinforcements from archways in the tunnel that you cannot enter.
Once you are out of Erebor, there is a signal light and, blocking the way to the City of Dale, a Fire Drake nest (that you could capture with the Untamed Allegiance power to recruit fire drakes). Prior to entering the eastern wing from the outside, you would, however, have needed to run the gauntlet of four catapults on two platforms.

Heroes can reach level 10 in this mission.