What Lord of the Rings game would be complete without the Fellowship of the Ring? Throughout your travels, you'll meet (and join) such characters as those listed below. They, along with the principle cast, will have their own abilities and magic.
Gandalf
Race: Wizard, Order of the IstariWeapon of Choice: Sword and Staff
Gandalf is the wisest of all beings on Middle Earth and the commander for the entirety of the War of the Ring. His duty, especially after becoming Gandalf the White, is to help the free peoples of Middle-Earth become finally free at last. With the help of his Fellowship, Gandalf is finally able to pursue his goal.
Though Gandalf does not actually join your party for any extended period of time, Berethor and the gang are forced to assist him in his most epic battles. When Gandalf is taking on the Balrog, for example, Berethor is there. When the Witch King appears on Pelennor Fields, you will also be there. Worry not though, because this Wizard is just as much a match for anyone as he ever has been.
Aragorn
Race: Human, King of MenWeapon of Choice: Sword
Aragorn is the King of Men, and captain of the Rangers from the North. From an early age, Aragorn was raised by the Elves in Rivendell. The elves, knowing that one day he would have to pursue his destiny, prepared him for the trials ahead. With the help of the rest of the Fellowship, Aragorn came into his own and took his place as the rightful King.
Aragorn does not join your party, though he is in it for a number of battles, ranging from Helm's Deep to the battle of the Pelennor Fields. As would be expected from such a Ranger, Aragorn is incredibly skilled at what he does, and deals the most devastating of attacks from the Fellowship's standpoint.
Legolas
Race: Elf, from MirkwoodWeapon of Choice: Bow
Legolas is a Prince of Elves from Mirkwood Forest. He is thousands of years old, and possesses the knowledge and skill to proeve it. When he is summoned to the Council of Elrond, he binds himself to the Fellowship, and eventually helps to save all of Middle-Earth.
Legolas is only in your party for one battle, in Helm's Deep. That is not to say, however, thath e is not extremely powerful in that battle. WIth his help, defeating the Uruk-Hai that are rampaging the great fortress is easy.
Gimli
Race: Dwarf, Durin's LineWeapon of Choice: Axe
Gimli is a great Dwarf of Durin's Line, hailing from the Erebor. He is proficient in battle, dealing devastating damage with his greataxe. His summons to the Council of Elrond landed him a place in the Fellowship of the Ring, where he helped the others to vanquish many foes and save the world.
Gimli is also only in your party for one battle, in Helm's Deep. His attacks don't deal quite as much damage as one might expect, but he easily takes out enemies nonetheless.
Eomer
Race: Human, RohirrimWeapon of Choice: Sword / Spear
Eomer is the captain of Rohan's Rohirrim Soldiers, and nephew of King Theoden. Despite his surrogate father's mood, Eomer is more than willing to assist his country in any way possible. He technically is not a part of the Fellowship of the Ring, but he does aid them a great deal in their quest.
Eomer is never in your party in this game, being only an NPC. You never see him fight or fight as him, but he is in a number of videos and NPC-controlled moments.
Eowyn
Race: Human, Shield Maiden of RohanWeapon of Choice: Sword
Eowyn is the incredibly strong-willed neice of King Theoden of Rohan. When the King falls ill, it is her that tends to him, and when he recovers she continues to be by his side. When her country goes to war, she does everything within her power to join the battle. And at the last, she does a greater thing than many ever do: she kills the Witch King of Angmar.
Eowyn is only in your party for one battle: the one against the Witch King. She isn't the strongest warrier, nor is she the weakest. Her skills are sufficient for the battle, allowing you to finish the Witch King at your leisure.
Theoden
Race: Human, King of RohanWeapon of Choice: Sword
Theoden is the once-great-then-not-so-great-then-great-again King of Rohan. After a time of sickness for him, he comes back and takes reigns as his country goes to war. With the aid of the Fellowship, King Theoden goes to Helm's Deep and then to the fields of Pelennor, where he meets his untimely end.
King Theoden is never in your party, but just like Eomer you see him in a number of movies and IGC's.