When Aster and the others heard from Vivian about her manual's first technique, they couldn't agree more with the name of her profession being "Miracle Alchemist" as in it would be a miracle for someone like that to appear.
Just think about it, to obtain this technique a mortal would need to consume hundreds of toxins and materials with detrimental effects and remain in a healthy state, without the need for antitoxins according to the white-haired girl's explanation.
Besides someone like Vivian who even as a mortal has an extreme immunity to any toxins, no one else can fulfill such a condition, well, maybe Aster with his insane vitality and recovery abilities can survive after consuming all that, but he would for sure end up feeling sick while his body cleanses all those toxins in his current state, so he'll fail the requirement at the end of the day.
