Parabatai are a pair of Shadowhunters or Nephilim warriors. They fight together and have a closer relationship. They are not only best friends and even more than siblings. They are partners who are willingly to die for each other. Jace Wayland and Alec Lightwood are Parabatai. It is told that their fathers were also Parabatai. In the story, it is also known that Valentine and Luke were also Parabatai.