The 'Foglet Dedoction' is a type of potion. It was the product of Alchemy. One's attributes would increase upon ingestion. However, not anyone could just down it. Alchemical ingredients were highly toxic to regular humans.
Olivia was not actually interested in things like using foreign materials to increase her attributes. After all, this was a game, and she was a hacker.
However, these 'Witcher Quests' provided extra rewards, so why pass up on this?
Olivia did not act rashly. In reality, Olivia had an abnormal amount of experience in fighting monsters and creatures, as she possessed all the abilities of 'Jane Doe Su.' She could rely on her dodging abilities to make herself invincible to monsters. That is right, that was her unrivaled tumbling!
Tumbling might end up being highly useful in this Source World. Perhaps all gaming worlds used it as a staple mechanic?
