Here you’ll find all the Trophies/Achevements that are obtained by completing story missions. None of these can be missed. There will be spoilers - you have been warned.
One has walked in Mordor.
Obtain every other Trophy in the game to obtain the Platinum Trophy.
Make an uruk yours.
Interrogate your first Uruk. This will happen at the beginning of the game.
Get Ratbag promoted to Warchief.
Complete the mission “The Warchief” .
Discover some of the Wraith's past.
You’ll get this Trophy/Achievement during the mission “An Interested Party” .
Destroy the Monument Gate and topple the statue of Sauron.
Complete the mission “The Dark Monument” .
Kill The Hammer.
Complete the mission “The Black Captain” .
Save Lithariel's life.
Complete the mission “The Rescue” .
Lift Lady Marwen's curse.
Complete the mission “The Power of the Wraith” .
Kill the Great White Graug.
Complete the mission “The Great White Graug” .
Kill the Tower.
Complete the mission “Lord of Mordor” .
Kill the Black Hand.
Complete the mission “Mordor in Flames” .
Witness the creation of The Rings of Power.
Complete the mission “The One Truth” .
Brand all 5 Warchiefs.
You will have to Brand all five Warchiefs in Nurn before you can begin the quest “Lord of Mordor” . You can, however, start making progress on this objective after completing the mission “Power of the Wraith” .