It might be waver, with the way the throne works, he might have become a hero in the future and still be apart of the Reality Marble since he declared his loyalty.
Short summary of Waver's life post 4th Heaven's Feel:
Saved the Archibald family from ruin. Granted the title of "Lord El-Melloi II" and inherited Kayneth Archibald's Mystic Code (and turns it into T1000). Became a lecturer at the Clock Tower and taught Tohsaka Rin. Returned to Fuyuki and with Rin, helped to dismantle the Grail War system.
