It still doesn't sit right. Maybe it's because Riku doesn't put much stock in deities or grand destinies. Maybe it's because he's stubborn.

That's one thing that hasn't entirely faded with age.

He listens attentively, at least, before speaking. He should choose his words carefully.

"And she's the only one? No matter what happens, someone has to give up so you can pursue your duties."

Maybe there's something to be said about self-sacrifice. About the many over the individual. Sora'd probably jump at that kind of sacrifice in a heartbeat.