Even if I live a worthless life for you, there's still someone I cannot leave behind. There's someone else I can't leave behind yet. There are so many lessons I still need to teach him, he tells his father. Even though humans are stupid, he says, he still needs to stay alive because he needs the reaper's power. The reaper is the first one he's defeated, and even though he knows that humans are dumb, he'll still have to kill him.