CLEAN : New M. Night Shyamalan thriller Split hits theatres

The transcript discusses the development of a movie script over 15 years, focusing on the challenge of portraying nine distinct characters sharing one body. It explores the dynamics of cooperation among personalities, the protagonist's ability to manipulate them, and the role of instincts and nature in the narrative. The film blends reality with fantastical elements, highlighting the protagonist's survival instincts and understanding of the natural world.

In what way does the character Casey's background influence her instincts?

What is the relationship between reality and the fantastical elements in the movie as described?