Mrtyu

Mṛtyu (from Vedic Sanskrit: मृत्यु IAST:mRtyu ; Latin cognate mortis), is a Sanskrit word meaning Death. Mṛtyu or Death is often personified as the demigods Mara (मर) and Yama (यम) in Dharmic religions such as Hinduism and Buddhism.

Mara (Hindu goddess), the goddess of death according to Hindu mythology.

Mṛtyu-māra as death in Buddhism or Māra, a "demon" of the Buddhist cosmology, the personification of Temptation.

Yama (Sanskrit: यम) is the lord of death in Hinduism and Buddhism.

Yama in Hinduism.

Yama in Buddhism.

The Brhadaranyaka Upanishad (a mystical appendix to the Shatapatha Brahmana and likely the oldest of the Upanishads) has a creation myth where Mṛtyu "Death" takes the shape of a horse, and includes an identification of the Ashvamedha horse sacrifice with the Sun:

Then he became a horse (ashva), because it swelled (ashvat), and was fit for sacrifice (medhya); and this is why the horse-sacrifice is called Ashva-medha [...] Therefore the sacrificers offered up the purified horse belonging to Prajapati, (as dedicated) to all the deities. Verily the shining sun [ye tapati] is the Asvamedha, and his body is the year; Agni is the sacrificial fire (arka), and these worlds are his bodies. These two are the sacrificial fire and the Asvamedha-sacrifice, and they are again one deity, viz. Death. (BrUp 1.2.7. trans. Müller)