wat the fat man in orange suit is and fate

Rating: Null/10 (3 August 2004)

I have seen Donnie Darko over and over its the greatest film ever made but there are two characters i cant grasp. Sharita the Chinese girl and man in orange suit. I can look extremely deep and class them as the devil and guardian angel as Sharita has a book on Donnie maybe she just admired him or was it his book of destiny because when he says every thing is going to be OK she screams and runs is this because she knows whats going to happen to him and that he had dodged fate and everyone would be effected? The man in orange suit is only seen twice he stops Donnie from kissing Gretchen for first time maybe this is because he wants Donnie to stay alone also when its the Halloween party he is outside again and Gretchen comes goes to grandma deaths house with Donnie and dies the devil had want he wanted in getting Donnie to be alone but Donnie notices what he had done and when Gretchen had died he realized he was meant to be alone and had gone down the path of evil in dodging his death then goes back in time to follow gods path. Am i looking to deep on these characters ?? are they just put there to side track u.