Mrtyu

Mṛtyu (मृत्यु), is a Sanskrit word meaning death. Mṛtyu, or Death, is often personified as the deities 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 (यम) is the god of death and the underworld in Hinduism and Buddhism.
 * Yama in Hinduism.
 * Yama in Buddhism.

Etymology
The Vedic mṛtyú, along with Avestan mərəθiiu and Old Persian məršiyu comes from the Proto-Indo-Iranian word for death, *mr̥tyú-, which is ultimately derived from the Indo-European root *mer- ("to die") and thus is further related to Ancient Greek μόρος and Latin mors.

Vedas
Mrtyu is invoked in the hymns of the Rigveda: "Depart, Mṛtyu, by a different path; by that which is your own, and distinct from the path of the gods; Ispeak to you who have eyes, who have ears; do no harm to our offspring, nor to our male progeny."

Upanishads
The Brhadaranyaka Upanishad (a mystical appendix to the Shatapatha Brahmana and likely the oldest of the Upanishads) has a creation myth where  "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."

Padma Purana
Mrtyu fights in the war between the devas and the asuras in the legend of Jalandhara.

Mahabharata
The Mahabharata references a legend regarding a dispute between Time, Mrityu, Yama, Ikshvaku, and a Brahmana. Mrityu is female in this legend.