The Path of Thorns is a Path of the Road of Lilith found in Vampire Twentieth Anniversary Edition: The Dark Ages.
The Path of Thorns is one of the more philosophical Paths on the Road of Lilith. To them, wisdom is hidden in flesh and mud, and a careful academic study of physical pain will lead to enlightenment. Many who follow this path are interested in alchemy, and may hold the (somewhat heretical) position that Caine and Lilith together created vampires, not just one or the other.
They are one of the more organized among the Bahari cults, and gather as regularly as possible to share their research and prove their wills against various ordeals of suffering.