SCI FI Wire listed the "10 coolest, scariest, funniest and/or most fascinating characters" they have seen this fall:
Castiel on The CW's Supernatural
Played by Misha Collins. Last season, Collins was brought in to play the angel Castiel for few episodes. Well, the producers knew a good thing when they saw him, and Collins became a full-fledged regular this season. While we loved seeing a hedonistic future Castiel when Dean (Jensen Ackles) hopped forward five years to see what had become of the world, we actually love Castiel even more just as he is. Castiel can be scary, grim and hysterically funny. Beyond that his chemistry with Dean is priceless.
Source: SCI FI Wire.