The Witches' Tea Party Episode 12

Subaru awakens in the graveyard with Emilia lying nearby. This time, he makes up his mind to save not only Emilia, but everyone in the Sanctuary and Roswaal's mansion from the threats that hang over them. Roswaal makes it clear that he will use Subaru's power to keep starting over by force if he has to, if it will allow him to achieve his own goal. What is driving Roswaal to go to such lengths? In search of the answer to this and many other questions, Subaru goes to see Echidna once again.