Ketu is the moons southern node, considered as a half planet in Hindu mythology and called a shadowy planent because of its invisibility. Ketu is believed to be the body of Rahu, after Lord Vishnu cut off the head of asura. Ketu is both evil and beneficial, it causes loss and sorrows and at the same time it turns individual towards God. Ketu yantra is used to bring down the negative effects of Ketu on an individual and also to strengthen its positive effects. The Yantra heightens the peace of mind, blesses the devotees with tranquality and harmony and also cures illness.