Dushana is one of the demon-king Ravana's brothers in the Ramayana, the earlier of the two major Indian epics.
Dushana, along with his brother Khara, seeks vengeance for their sister Shurpanakha, whose ears and nose were severed by Rama's brother Lakshmana.
Rama smashes the army and kills Khara and Dushana in a hard fight with their demon (supernatural entity) army.
Shurpanakha seeks revenge against Ravana after seeing her two brothers' downfall.
Ravana understands he won't be able to kill Rama in combat, so he decides to revenge his sister by capturing Sita, Ravana's wife.
This puts in action the narrative of the epic's second half.
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