Many see Kakashi as this cold, uncaring individual who would do anything to complete a mission, and while that's not entirely false, he's a much better person than that. After Obito gave Kakashi his sharingan and Rin dying, he became colder. A person can only lose so many loved ones, after all. He's always wearing a mask over his face, it only covers the lower half of his face, wanting to keep his physical identity a secret from everyone.