ok so people are saying this is the fault of the goddess, I don't think so
I also don't think she is telling Jun that this is her fault, What I'm getting from this chapter is that the goddess is telling her
that this whole mess happened cause she didn't do what she said she would do
Jun was told she is the only one who can help, she accepted and then she ran away from it
she ran from her responsibilities that she accepted and these are the consequences of those actions
it's like in DnD, the party gets to a town for a subjugation quest but the monster is a bit too scary or trouble so the party decides to leave, they return 2 weeks later and behold the whole continent is destroyed and the monster is killing everybody
why? well the guys who were supposed to fix this Left for 2 weeks
it ain't the DM's fault that the players decided to not do the job they were hired for, and it isn't the player's fault for not wanting to do it. But it was their responsibility.
same with Jun, it ain't her fault Marcus went crazy, but it was her responsibility to kill the demon king, which she failed to do and these are the consequences for the choices she made.