Saoshyant (Avestan: Saoš́iiaṇt̰) is the Avestan language expression that literally means "one who brings benefit", and which is used in several different ways in Zoroastrian scripture and tradition. In particular, the expression is the proper name of the Saoshyant, an eschatological saviour figure who bring about Frashokereti, the final renovation of the world in which evil is finally destroyed. The term was contracted to 'Soshans' in Zoroastrian tradition, and came to apply to three saviour figures that progressively bring about the final renovation.
In the Gathas, the most sacred hymns of Zoroastrianism, believed to have been composed by Zoroaster himself, the term is used as a common noun to refer to the prophet's own mission and to his community of followers, who "bring benefit" to humanity. The common noun also appears in the Younger Avesta (e.g. Yasna 61.5), where it generically denotes religious leaders, including Zoroaster (e.g. Yasna 46.3) Another common noun airyaman "member of community" is an epithet of these saoshyants. In contrast, the standing epithet of the saviour figure(s) is astvat-әrәta "embodying righteousness," which has arta/asha "Truth" as an element of the name. These saviours are those who follow Ahura Mazda's teaching "with acts inspired by asha" (Yasna 48.12).
'Saoshyant' first appears as a proper name in the Younger Avesta, explicitly so in Yasht 13.129 where it is used in the singular and where Astvat-ereta develops into an alternate name of the Saoshyant. The singular also appears in Yasna 59.1 where Verethragna is said to be Saoshyant's weapon in overcoming resistance. A plural form appears for instance in Yasht 17.1 where Ashi—the divinity of "recompense"—is described to give the Saoshyants the power of "making wonderful" (frasho.kereti).
The role of the Saoshyant, or Astvat-ereta, as a future saviour of the world is briefly described in Yasht 19.88-96, where it is stated that he will achieve the Frashokereti, that he will make the world perfect and immortal, and evil and Druj will disappear. He is identified as the son of Vîspa.taurwairî and it is stated that he will come forth from Lake Kansaoya/Kansava and will carry the same weapon Verethragna that a number of Iranian epic heroes and kings have used in the past against various demonic foes. Haurvatat, Ameretat and other similar entities will be his companions and together, they will vanquish the evil creations of Angra Mainyu.