Novigrad- Sold by the Halfling Herbalist in Novigrad.Time slows down after killing an enemy by 50% Skellige- The manuscript and potions of this can be sold by Gremistīlizzard Improves reflexes and prolongs reaction time.In addition, the witcher's blood injures and knocks them back when they wound him.
Superior Black Blood Vampires and Necrophages start Bleeding when near the witcher.
South of Hierarch Square, and across the canal. Black Blood Witcher's blood injures Vampires and Necrophages when they wound him.
