There was an outsider that was some type of leader of dragons that the MC had to confront. When that happened the outsider used an ability to spawn dragons from his own body. MC defeated him and implanted a magic stone in his chest to replicate that ability.

I'm reading this a bit later than the other comments here, so I'm sure the story clears up more later on. But I believe this vision was caused by Aisha's light element. Aisha is not Zenos, the Procreator says himself that those that have sinned cannot die before they have repeated their sin, killed their lover(Ignis), killed their child (Zenos), Killed their parent (Procreator). It makes more sense that Abel is the most recent child of Zenos, that's the only reason that she would have given that warning to the Duke. Since Aisha originally died early in the story she can not be Zenos, also the warning doesn't apply to the MC because her memories of her past life are those of a different world, not of her past sins. It also doesn't make sense for Abel to be the reincarnation of Procreator because the Duke isn't his biological father so I don't know if that would fulfill the Creator's punishment. Unless Procreator is trying to grant himself immortality by making impossible for him to kill the human that sired him so he can kill the Creator. Which might be brilliant if it worked that way. But Persona was told from the perspective of Abel and it never mentioned Procreator.