Fate/Zero - Speculation & Theories (for F/SN Game Players)

This Speculation & Theories thread is intended for people who have played the Fate/Stay Night game, but have not read the Fate/Zero light novel series. This thread allows you to speculate about what you think will happen in Fate/Zero using your knowledge of the F/SN game.

No information from the Fate/Zero source material is allowed even under spoiler tags.

All information from the Fate/Stay Night game is permissible without spoiler tags.