There is a big hint or reveal in the latest Doctor Who Season 8 Trailer..

 

This is the newly released trailer. Watch it! “I see into your soul, Doctor”

“I see into your soul Doctor,” a nasty voice bellows. “I see beauty, divinity, hatred!

 

 

Apparently some big villain is returning. It might be be a Dalek, or

 

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Davros, the Emperor Dalek or Dalek Caan!

 

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Source: Digital Spy