Who was the true main character of this story?
Initially, a lot of it was done through Andrew's eyes, but Matt is the one who ultimately changes the most and becomes the hero, while Andrew sinks into insanity and bloodlust. Andrew is the villain, and Matt is the one who tries to reason with him, then has no choice but to kill him.
"Lives with no meaning go straight past you, like trains that don’t stop at your station."