This can't bode well for Dean Winchester...
... but it makes sense following the shocking cliffhanger that concluded Supernatural Season 9:
Our beloved Dean is now a demon (or at least has the eyes of one at this point), so the King of Hell himself must be playing a key role this fall, right?
The CW has confirmed that Mark Sheppard will be a series regular on Supernatural Season 10, joining Misha Collins in that capacity, as the network also announced this month that Castiel will return to a full-time role next year.
No word yet on just how many episodes will include Crowley, but it's safe to say he'll be around a quite often to make life miserable for our demon hunters.