Determination of a Planet as Malefic or Benefic
Needless to say, we all know the classification of planets as being natural malefic or natural benefic. Jupiter, Venus, Moon are considered natural Benefics. Sun, Mars, Saturn, Rahu and Ketu are natural Malefics. Mercury is natural Neutral.
However, individually for a native a natural benefic planet can functionally turn into a malefic. The Moolatrikon sign of a planet brings in this functionality. As a rule, for a given lagna; If a mulatrikona sign of any planet falls in the 6th, 8th, or 12th houses, then the planet ruling that sign becomes a functional malefic for that person.