<Speculation>
So these other houkousha origin stories raise questions about what we saw in chapter 1. None of the stories had figures trying to stop the monsters that killed them but Manatsu saw another version of his female self. Since the other houkousha did not recognize Manatsu's figure upon his reincarnation it suggests that he is actually the original and so the other version of Manatsu in chapter 1 would be his future self.
So then why would a future version of Manatsu be trying to stop the monster that kills him in chapter 1? That would prevent him from becoming a houkousha in the first place. That's odd if he's supposed to be a 'savior' given how inclined he is to help others.
Because of this I'm guessing the twist is he is no savior at all but rather a pariah who would bring some kind of calamity to the others.
@jasty
Psycho Play would drop the series if there is time travel. Blehhhhhhhh💀
Though I will say, I think Manatsu is in the body a hero of legend based on the fact that her visage is depicted on the shield’s crest in the first chapter.
@Lee-Nyan I don't think her body being in a prophesy answers the question of who was occupying it at the beginning of Chapter 1. I guess it could be a past incarnation but it would still need to be from a different time or a different dimension since none of the others recognized it after Manatsu's reincarnation.
Or maybe they do recognize it and are hiding the fact...
@jasty I’m thinking that time isn’t exactly parallel between the two worlds. Kikyō was in fuedal japan, Percival was in Medieval England, and Dici was likely from Ancient Rome. I’m thinking long ago the Katana Woman (my guess her name is either High Priest Alvan or at least fought with them) chased the Skull Knight into modern Japan and lost her way back home when Manatsu sacrificed himself. Then Manatsu woke up like centuries later. They mention that the Holy Water Bath that High priest Alvan created has the power to purify corruption. The same power Manatsu now wields.