While talking about his own character Sirius Black, Gary Oldman mentioned that he wished that he had the ‘whole picture’. In the third film, Sirius was painted as as mass-murderer and a traitor, but as the book progressed, it turned out that he was actually good. When Oldman asked Radcliffe if he knew the future of his character, the actor answered, “Just Rickman. Rickman had the inside line.” Oldman was stunned and said, “Rickman? He worked that one out!” Radcliffe revealed that ‘very early’ on, Rickman had wanted to know the future of Snape’s story and asked series author JK Rowling. He never told anyone. Even director Chris Columbus would try asking him about certain scenes and he would just say, “I will tell you later.”
To Empire magazine, Rickman had revealed that he did not want to return to play the character as he felt that it was ‘nothing more than an unchanging costume’. However, author JK Rowling had told him the secret about his character, as well as the story behind the word ‘always’.
For the first several books, Severus Snape appears to be a sinister bully, who the headmaster Albus Dumbledore trusts for what appears to be an unfathomable reason. It later turns out that he was playing a double agent at great personal risk, and was fighting to protect Harry from Lord Voldemort, as he had ‘always’ been in love with Harry’s mother. Rickman in 2011 had told HitFix that Rowling had given him ‘one tiny, left of field piece of information’ about Snape. He said, “It helped me think that he was more complicated and that the story was not going to be as straight down the line as everybody thought.” This helped him realise that he was playing a rather ambiguous character.