My first rewatch since 2019. This is all about Kevin. He is the point of convergence. This is his story. Elijah's vulnerability is easily breakable bones. David's vulnerability is water. But Kevin himself represents the ultimate vulnerability. His very presence on the screen is painful to witness. He is unable to bear existence, which is why his appearances are so short. Superheroes tend to have two identities, one of which is their true essence and the other is a disguise. The Horde has 24 personalities, but only one of them is the essence, and that's Kevin. The title makes more sense now too. Unbreakable was about David and Elijah, representing the literal (inability to break bones) and the metaphorical (strength to overcome obstacles) senses of the word. Split was about The Horde and Casey, again in the literal (the personality split) and the metaphorical (alienation, being split from the society) senses. Glass represents many qualities: it can be broken, it can be fragmented (or split), it creates reflections (again, literal and metaphorical). It has these qualities because it's vulnerable. This movie is about vulnerability. This is why David gets drowned in a puddle of water. Why Elijah has his bones broken. And Kevin? Well, he finally dares to come out. He lets himself exist, but his very being is in so much pain that he physically cannot inhabit this world. So he gets a sweet relief of death. Keep in mind that if he kept hiding, The Beast would take the bullet, and it wouldn't do him any harm. Even the main villain of the story has this vulnerability permeating her every action. At every step of the way, she is terrified and doubtful and empathetic. She knows what they're doing is wrong, but she cannot let superhumans come to existence. Because weak, vulnerable humans would have no place in such a world. She is afraid because she is vulnerable herself. She fails to realize, however, that neither Elijah, David nor Kevin have ever overcome their vulnerabilities using their superpowers. These superpowers do not help with that. The final revelation had to happen precisely because she had to face this new world that she was so terrified of.