Board Thread:Metal Gear Solid V/@comment-4016602-20150822143602

Usually, the game's subtitle is related with something present in the game:

MGS2: Sons of Liberty, the terrorist group called Sons of Liberty

MGS3: Snake Eater, The Operation Snake Eater

MGS4: Guns of The Patriots, Liquid's plan to destroy the Patriots

MGS: Peace Walker, Project Peace Walker

So, what do you think "Phantom Pain" could mean? 