Padmasambhava is where Buddhism arrived in Tibet and did not so much replace the existing religion as recruit it. The traditional account has him subduing the local mountain gods and demons one by one and binding them by oath to protect the dharma instead — which is a fair description of what actually happened to Tibetan religion. The Nyingma school traces itself to him and to the terma system he is said to have established: teachings hidden in caves, lakes, and in the mind-streams of future practitioners, to be found when the age is ready for them. It is an institutional mechanism for legitimate innovation, and it is still in use.