In Vedic astrology, Mars, Saturn, Rahu, Ketu and Sun are considered cruel planets. Mars is the cruelest planet afflicting the birth horoscope of a person. If placed unfavorably, Mars is the most damaging planet for the married life.
Mars positioned in first, second, fourth, seventh, eighth or twelfth house in a Kundali creates Mangal Dosha. Mangal Dosha should be checked not only in Lagna chart but also in Moon chart and Venus chart. A person is Non-Manglik only if none of the three charts is afflicted by Mars. Mangal Dosha is also known as Kuja Dosha and Bhauma Dosha. The person having Mangal Dosha is known as Manglik.
Link :
https://www.drikpanchang.com/jyotisha/mangal-dosha/mangal-dosha-calculator.html
