Sam and Dean Winchester: they are monster hunters. Dean: hes a hunter. Sams older brother hes cool, likes AC/DC and classic rock, owns the 1967 chevy impala, hes not the best at flirting, hes got humour. 
Sam: hes a hunter. big nerd. hes sweet, tall, has a bit of humour.
 Castiel: hes a fallen angel, hes innocent and sweet. hes not good with social skills and speaks in a very monotone way.
They are great friends.

Sam is your twin brother who is older by 6 minutes, Dean is your older brother.