After Bhooth Bangla, team Priyadarshan will gear up to release the action-thriller Haiwaan. The main cast of the film comprises Mohanlal, Akshay Kumar and Saif Ali Khan in leading roles. During an exclusive interview with Filmfare, the writer spoke about working on the film, while sharing a thing or two about Saif Ali Khan's character. When Filmfare asked which character was the most challenging to write, Rohan said it was Saif Ali Khan's. He revealed, "I think Saif sir's character was very challenging. He is one of the main characters.