Who is a character from Lord of the Rings?

The first and primary protagonist in the Lord of the Rings is Frodo Baggins, close relative to Bilbo Baggins from The Hobbit. However, in Book 2, Tolkien splits the story into three storylines. Frodo continues as a protagonist; however, now Aragorn, Merry and Pippin are also protagonists, the story following all of their perspectives as the world of Middle-earth readies for war.