Disciples is a Tier II promotion for the Warrior Monk in Civilization VI. It requires Shadow Strike or Twilight Veil.
Effects
When defeating an enemy unit, spread their religion to nearby cities.
Civilopedia entry
It's a truism of the martial world that when the disciple is ready, the master appears. And sometimes, the disciple isn't ready at all and the master delivers a savage beating which the disciple will feel inspired to tell all of his or her friends about.
Some adherents would not only take on the techniques of the master, but the spiritual and religious systems bound up in those techniques—traveling from village to village, nation to nation.