That was the whole argument Rit was having with Theodora though.

Who is Theodora to demand that Ruti be her savior? Theodora's only answer was her own interpretation of God's will, which Rit then also denied had any merit. Theodora and the other party members are all strong. They could all form their own hero parties and defeat the demon lords.

But Theodora and Ares demand that Ruti do it for them. Ares because he is compelled to bask in Ruti's glorious victories and satisfy himself that she won because of his support (when she's proven time and time again that she doesn't need him at all). What Ruti did want is emotional support, which Tisse provided better than any of the companions did so far, and Gideon was the only approval she ever wanted. Theodora wants the holy victory, but Rit pointed out that she was too scared to do it herself.

Theodora was belittling everyone she's ever come across, including herself, by believing that only a person with the Hero's Blessing can ever actually be the hero.

I'm very confused on where the Demons stand in all this. They seem to philosophically agree with Rit, but also want to ensure that Ruti's blessing overwhelms her. Maybe there's something we haven't been told, that the demons already know (evidence by his comments about her weapons and that these better copies will force her to become more controlled by the blessing). My only guess is that the Hero's Blessing will result in the holder to also become the demon lord once they kill the current one? Or something like that.