As an Angel of God, Castiel is an extremely powerful being. Merely perceiving his actual form typically results in blindness, as the appearance of his natural "visage" is so overwhelming that it is capable of burning a individual's eyes from their sockets, including those possessed by a demon. However, according to Castiel himself, certain "special people" are able to tolerate his true appearance and voice. He initially believed Dean to be one of these special individuals, yet his ignorance led only to two failed attempts to contact Dean. Apparently, one can protect themselves from such personal damage by shielding their eyes, and perhaps their ears, from the presence of a Angel, as demonstrated by Sam and Dean in "Heaven and Hell".
Castiel possesses astounding power, though his abilities are apparently not completely limitless. He is apparently immortal and invulnerable to mortal harm. At the end of "Lazaras Rising", he absorbed several shotgun blasts directly to the chest of his host, which did not so much as faze him. He is capable of possessing a Human and fully utilizing their body, yet he claims that his host is, or possibly was, a "devout man who prayed for it". This possibly indicates that Castiel is adverse to possessing a sentient being, and would not had done so if the man had not prayed for it, though he has not appeared to be particularly fazed by this. Castiel typically displays very little emotion and always exhibits an extremely somber disposition. He has not been observed to smile or express any strong emotions. According to the fallen Angel Anna, Angels possibly do not possess the ability to truly feel emotion. However, Castiel frequently exhibits what could be referred to as friendly affection towards Dean, and seems to at the very least come close to expressing regret, hesitance, and anger several times.
Castiel possesses astounding power, though his abilities are apparently not completely limitless. He is apparently immortal and invulnerable to mortal harm. At the end of "Lazaras Rising", he absorbed several shotgun blasts directly to the chest of his host, which did not so much as faze him. He is capable of possessing a Human and fully utilizing their body, yet he claims that his host is, or possibly was, a "devout man who prayed for it". This possibly indicates that Castiel is adverse to possessing a sentient being, and would not had done so if the man had not prayed for it, though he has not appeared to be particularly fazed by this. Castiel typically displays very little emotion and always exhibits an extremely somber disposition. He has not been observed to smile or express any strong emotions. According to the fallen Angel Anna, Angels possibly do not possess the ability to truly feel emotion. However, Castiel frequently exhibits what could be referred to as friendly affection towards Dean, and seems to at the very least come close to expressing regret, hesitance, and anger several times.