Unbreakable was something of a journey of discovery, as Bruce Willis’ David Dunn found out what he was capable of and that the idea of superheroes and supervillains was not quite as fantastical as it once seemed.
Along with him for the journey was his son Joseph, so to see Joseph remain a part of the story in Glass feels right.
In describing this, M. Night Shyamalan also compared it to Richard Linklater’s Boyhood, where actor Ellar Coltrane grew up onscreen.