As we continue our quest to backtrack and provide manuals for our older expansions, I give you The Reaper's Due long overdue manual! (Does that qualify as a pun?)
The manuals are available through a link on The Reaper's Due store page. https://store.steampowered.com/app/449980/Expansion__Crusader_Kings_II_The_Reapers_Due/

Key features:

• Start a game at any point between 1066 and 1337 and play until 1453
  
• Pick a Christian lord and make sure his dynasty survives as you play a succession of his descendants through the ages
  
• Gain Prestige for every successive character you play, furthering the glory of your Dynasty
  
• Expand your feudal domain - and keep it from falling apart
  
• Unravel the plots of your courtiers and vassals, each with their own opinions and agendas
  
• Take up the Cross and fight the Moor, the Heathen and the Heretic.
  
• Defend against the onslaught of the Mongol Horde
  
• Struggle with the Pope for control of the bishops
  
• Relive the Middle Ages with up to 32 other players in a competitive multiplayer mode
  

• OS: Ubuntu 16.04 x64
• Processor: IntelR PentiumR IV 2.4 GHz or AMD 3500+Memory: 4 GB Hard disk space: 2 Gb Video Card: ATI Radeon HD 6750 / NVIDIA GeForce 320 / NVIDIA GeForce> 9600 or higher. 1024MB graphics memory required.
• Memory: 4 GB Hard disk space: 2 Gb Video Card: ATI Radeon HD 6750 / NVIDIA GeForce 320 / NVIDIA GeForce> 9600 or higher. 1024MB graphics memory required.