Although 7 of the 8 cardinal directions are ruled by gods, the southwest direction is governed by a demon god named Niruthi, according to vastu shastra.
Niruthi’s weapons are a sword and a shield and he is a meat-eater. This lord is short-tempered and displeasing will bring bad luck. So make sure you take special care and attention to honor this directional lord. The first step is to reduce the width of the southwest side as much as possible, after consulting a vastu acharya. Water storage tanks, septic tanks and wells should not be placed in this side. According to vastu shastra, family quarrels, money loss, mysterious deaths and illnesses will be the result, if this directional lord is not pleased.