Walkthrough: Plains of Rohan 

Walk through the field until you come to a battle with two Elite Orc Sword Veterans and a Captain. These guys are tougher now, so be careful.

Quest: Save the Warrior
Enemies: 2 Elite Orc Sword Veterans and an Archer
Reward: 7420 exp

Continue on into a village. Here you'll come to another battle where Morwen will join your team. Fight through using Morwen's Duel Axe Skills and Idrial's Spirit Powers and this won't be too difficult.

Quest: Riders in the village
Enemies: None
Reward: 9900 exp

While in the village, collect the chests containing Defy Earth Phial and Kingsfoil. Head West in the village. You'll find a Save Point. Past that you'll find the Riders in the Village. To the South of those riders is a chest containing Leaves of Lembas

Quest: Riders on the East side of the Warg hive
Enemies: None
Reward: 14920 exp

Head East out of the Village. As soon as you leave, you'll see a group of riders in front of a cave. Approach them.

Quest: Riders on the West side of the Warg hive
Enemies: Random Battles with Hardened Greater Wargs, Wild Man Rabble, and
Reward: 14920 exp

Inside the Warg Cave, (entering from the East) take two rights to find a chest with Limelight Waters. Exploring the other path will get you into a battle that you are surrounded and outnumbered. Be prepared. After that battle, go left to find a chest with 2nd Age Elven Steel Greaves. Go to the right to find the Waters of Gladden. If you head straight, you'll go outside on a path, then back into an area with several chests. Pick up the Leaves of Lembas, Cracked Elfstone of Slashing Defense, Elf Medicine, Kingsfoil, and Defy Shadow Phial. Then go back to the entrance to the cave. This time, take the path that goes left and then take a right. You'll find the Ithilien Wool Captain's Cloak and Arnor Mushrooms. Next go back and head straight from the entrance. You'll meet up with more Rohan Riders. You may also reach these Riders by traveling South from the Riders near the village (thus circumventing the Warg Cave).

Quest: Riders near Edge of Fangorn
Enemies: Random battles only
Reward: 19800 exp

Pick up the Marsh Leeches next to the Save Point when you leave the Warg Cave. On the right side of the bridge, before you cross, you'll find a chest with the 3rd Age Dwarven Band of Might and Valinor Medicine. You won't be able to cross the bridge until you gather all of the Riders of Rohan. To do this, travel all the way back to the beginning of the Rohan stage.

Go back through the Warg Cave to the bridge. As you enter, you'll face a battle with six Elite Orc Sword Warriors. You'll face six more at the middle of the bridge after a cut scene. At the end of the bridge is an extremely tough battle. Here you'll fight 2 Uruk-hai Scout Veterans, 4 Elite Orc Sword Veterans, and 2 Elite Orc Archers. Use your Perfect Mode skills to win this battle. Also, make sure you keep using Elf Medicine to revive your fallen soldiers. Use your heavy hitters and Idrial in this battle so that people don't die so fast.

Quest: Reach the Great Hall
Enemies: Many random and planned battles with Elite Orc Sword Warriors, Wildmen, and Uruk-hai.
Reward: 22280 exp

Head into Snowbourne from the bridge. You'll immediately be attacked by two Wildmen and an Orc. To reach the Great Hall, you'll need to flip a series of switches to open different gates. First pick up the 3rd Age Rohirram Brooch of Haven in the chest in front of you. Next go to the left and head up the hill. On the right side at the top of the hill you'll find a chest with Loudwater Mists. Just to the West of it is a chest with the Gondorian Steel Captain's Guard Vambraces and the first switch. Next, look to the Eastern side of the plateau for another chest, holding Leaves of Lembas and a Defy Shadow Phial, and another switch.

Go back down and follow the lower path. You'll come to a Save Point and a chest with Limelight Waters. Below that you'll find a chest with Leaves of Lembas and a Defy Earth Phial and the third switch. To the North is the last switch in this area, next to a chest containing Lembas.

On the Right side of the town, you'll find chests containing Kingsfoil and the 3rd Age Rohhirim Guard Shield, as well as another switch.

At this point, you can head through in the center to the South. You'll run into a chest containing the 3rd Age Morgul Iron Piercing Axe. Follow the path up to another plateau. Pick up the chest on the West side to find Elf Medicine. Opposite of that is a chest with Rohirrim Iron Greaves. Flip the switch and head back down. All the gates should be open now. Go all the way around to the West side. If you are having trouble finding a switch, just use your mini-map as they are all marked on it. Follow the path up the hill to the Great Hall.

Quest: Liberate Snowbourne
Enemies: Two Uruk-hai Greater Captains and Grima Wormtongue
Reward: 14920 exp

As soon as you walk into the Great Hall, you'll be faced with this battle. Grima is immune to status changes, but has only moderate defenses against Piercing and Blunt attacks. He also loves to drain your AP. Knock out his two guards and then focus on him. Be ready to restore your parties AP with items. Use your melee fighters that don't rely on AP so much. Lastly, he used many Shadow Skills. If you use Defy Shadow Phials, it will reduce the strength of his attacks.

Quest: Morwen's Family
Enemies: Several Warg battles, Elite Orc Sword Veterans, Sharku the Warg Riding Captain
Reward: None stated

Collect the chests to obtain the Rohirrim Iron Pauldrons, Elf Medicine, Polished Elfstone of Water Protection, Kingsfoil, and Defy Shadow Phial. Next, turn the switch to open the exit gate. Go out the gate and into the cave. You'll be attacked by two Grizzled Greater Wargs. When the path splits in the cave, go to the left to find chests with 5 Loudwater Mists, Valinor Medecine, and the 3rd Age Rohirric Bronze Felling Axe. Go back and take the other past. Just past the save point is another battle with 2 Wargs. After this battle Eaoden will join you. Continue through the pass until you see a brief cut scene and are attacked.

Boss Battle: 2 Elite Orc Sword Veterans and Sharku the Warg Riding Captain.
Sharku is pretty tough and has a lot of HP, but is fragile to Water and Blunt attacks. Use Idrial's Loudwater Fury to deal some big damage. Eaoden also has some great Spirit powers (Drain Health, Channel Health) that you should try out in this battle

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