Upagrahas (sub-planets or shadow planets) are mathematically derived sensitive points in Vedic astrology, not actual celestial bodies. The primary upagrahas are: Dhuma, Vyatipata, Parivesha, Indrachapa, Upaketu (five derived from the Sun's longitude); and the more commonly used Mandi (Maandi) and Gulika — derived from Saturn's position based on the day of the week and the birth time. Mandi and Gulika in particular are considered indicators of obstacles, poison (actual or metaphorical), and karmic debts. Their conjunction with natal planets or house lords is read carefully in South Indian traditions especially for health and longevity assessments.