Chapter 4 is over and we're not even finished with the events in the synopsis? In many manga Volume 1 ends with chapter 4 or 5. So the publisher really put in spoilers from Volume 2 (and beyond based on this glacial pacing) in the synopsis; that would've been funny if it wasn't for the fact that it spoils future events beyond Volume 1.
Why can't he just tell Yuu he's the true hero and not him, anyway? (this really should've been addressed at the start) Is some ghostly witch from beyond the grave gonna choke him to death if he tells anyone? I'm sorry, but it's pretty dumb how the betrayal was set up. And what is he gonna do if his former friend decides to... grievously harm himself instead? Then the true hero is dead, GGWP.