'Yakshas' is a Sanskrit word which means 'brave and Strong' or "The swift travelling ghosts" in Mandarin.  But we are used to calling them Yakshas.  There are three types of Yakshas.  Some yakshas travel on the ground.  Others travel in space.  Yet others fly in the air. There are good yakshas and evil ones.The evil yakshas only feed on human beings and harm living beings.  The good yakshas uphold and protect the Buddha Dharma and give support and care to the cultivators.