In Middle-earth: Shadow of Mordor, the player play as a ranger by the name of Talion who has wraith-like abilities. In this game you will need Mirian or Runes. To get them faster and easily this guide will help you. Just do the way it is written down and you will get what you came for.
How to farm Middle-earth: Shadow of Mordor Mirian or Runes
First of all you have to start with a challenge mode: Trial of War. Then in the background play the Arctic Monkeys, after that you spawn captain and ear chiefs and wait for them to drop the runes.
It is not necessary to pick them up in the Test of Power mode, you can do it later in the story mode. Now you are in profit, you have the runes, now its up to you, what you wanna do with it. Keep it or convert it to Miriam its your choice. Keep on doing it until you get bored or had enough.
Here are some more tips for farming Mirian or Runes:
Its simple, you will just have to let the enemies kill you to get the vengeance bonus. You can send a death threat to a enemy in order to get the death threat bonus. Before making your final move just make a Warchief. Finally kill him by exploiting his vulnerability, this will give you 25 level rune.