Gondor, Rohan, and Dori

This is a fellowship meant to turn Théoden into a super-defender and all-around superstar, with Dori boosting him as necessary to keep Theoden from taking damage. The Rohan deck quests and provides defense for the Gondor deck, while Boromir does the killing, assisted by boosted Gondorians as necessary. Mutual Accord will let Rohan benefit from Gondor boosts, and vice-versa. Merry is a thematic choice to fill out the Rohan deck, and also keeps the threat down on that side, while Balin provides shadow protection and Théodred makes sure Balin has the resources needed to do his job. (Or Boromir, if he's questing.)