Several side missions, such as A Knife in the Dark and The Dark Rider, are direct references to J.R.R. Tolkein's works, with their titles being pulled directly from the names of chapters throughout the books.
Monolith Productions drew inspirations from sports games for the Nemesis system, in which narrative continues even though players fail at a match. This method can prevent immersion and narrative from being broken when players die in the game. According to one of the designers, Rob Roberts, the system is designed so that players can become emotionally attached to the protagonist through gameplay drama.
The areas, Udûn and the Sea of Nurnen, were re-imagined. Phil Straub, the game's art director, considered the most important part of creating the game's world to be maintaining consistency with the lore and to present "something visually new" that is realistic and corresponds with real-world environments. As a result, the team intentionally did not put too many fantasy elements in the game's world.
According to the development team, the team picked Celebrimbor as the Wraith because the character's backstory is interesting enough to expand the canon's authenticity, and that it could allow the team to write a story surrounding "power", which is one of the major themes of the game.
The tone of the game was described as "soul-crushing" by the game's director Michael De Plater. A way for the team to create a dark atmosphere was to introduce dark humor to the game, which can be reflected by the characters' dialogue and voice-acting.
After you hunt and kill one of the Morgul Bats, you'll unlock information on them in the Nature section of the Appendices. The page for the Morgul Bats details how the rotting flesh on their teeth makes for great poison reads, "Those Uruks that get poisoned become horrbily diseased and bloated, wearing their deformities as marks of honor. The poison slowly eats at their minds, sending them nightmares of a demonic man-bat who preys on fear". The "demonic man-bat" is a subtle reference to Batman.
The idea for the game's Nemesis system first started when the team at Monolith considered themselves experts at artificial intelligence and wanted to continue to push its boundaries. Wanting to allow players to choose and decide their story, as they considered it one of the major pillars in building a sandbox game, and to "leverage the new generation hardware through innovation", the team wanted to create a system that allows non-playable characters to respond to players' action. In order to give the system a good presentation, everyone in the studio was involved in it.
According to the game's director, Michael de Plater, the story aimed to create a character-driven story, so as to be "authentic" to the themes established by Tolkien, and was written by Christian Cantamessa, who was the lead-writer for Red Dead Redemption.
The Wraith, Celebrimbor, will often quote lines from The Lord of the Rings, while referencing events happening in the game. During Shattered Memories, after waking to find the Graug, Celebrimbor will call out "Fly, you fool" in reference to Gandalfs line urging the Fellowship to run during his fight with the Balrog. Upon returning to a Forge Tower, Talion sometimes asks what the Towers are. Celebrimbor will respond that they are a light in darkness of Mordor, when all others have gone out. This is a reference to the Vial of Galadriel, given to Frodo Baggins. Talion will make a remark about Torvin being a wanderer, to which Celebrimbor will respond "Not all those who wander are lost" which is a line from the poem "All that is gold does not glitter" written by J. R. R. Tolkien.
During the Banished From Death trailer, Talion's dagger, Acharn, can be seen as being broken about a foot along the blade, in a jagged fashion. This is very similar to Narsil, the blade that belonged to Elendil, and the one used by his son Isildur to defeat Sauron.
Early in the game's development, the development team approached and consulted film director Peter Jackson, who had handled the development of the Lord of the Rings films, and were advised not to develop a movie tie-in.
The game was set in between the events of The Hobbit and The Lord of the Rings because the team wanted to show the iconic elements of the universe, without being unoriginal, with the game's environment being inspired by both the books and the films.
In order to prevent adding inaccuracies to the game's world, Monolith consulted several Tolkien scholars from Warner Bros.. The company also collaborated with Weta Workshop, Jackson's design company, to work on the game's special effect and scenery items. When depicting the game's other characters which is already well-established in the series, the company partnered with Middle-earth Enterprises, the franchise rights holder, to prevent them from being misused and to prevent contradictory between the game's story and the original story written by Tolkien.
The game was initially pitched as a potential tie-in for The Dark Knight Rises (2012), where the nemesis system would be used to depict Batman fighting his way through Bane's henchmen in an occupied Gotham City. After some initial meetings, the filmmakers allegedly got cold feet at the idea and the project was re-purposed as a Middle-Earth tie-in.
The trivia items below may give away important plot points.
Many theories have arisen regarding The Black Hand of Sauron's identity after the game's ending. Some say the Black Hand is just another of Sauron's forms (given his ability to shapeshift as seen in this game and the Silmarillion). Others say that the "Black Hand" was just someone possessed by Sauron's spirit or, alternatively, that the Black Hand allowed him to at the game's end.
After the game was criticized for the anticlimactic boss battle against The Black Hand of Sauron, Monolith took consideration with this and made sure that the boss battle between Celebrimbor and Sauron in The Bright Lord DLC was much better.