01A mind fixed on dharma
When the three brothers did tapas and Brahma came to grant boons, Vibhishana asked that even in the worst distress his mind should stay on dharma, and that the Brahmastra should come to him without being taught. Brahma was so pleased that he gave him immortality as well, unasked. In Lanka he lived as a rakshasa among rakshasas and never forgot his boon. When Ravana ordered the captured Hanuman put to death, it was Vibhishana who stopped him: an envoy is never killed. So the punishment became the burning of Hanuman’s tail.
02Spurned in Ravana’s court
As Rama’s army reached the shore, Vibhishana told Ravana again and again to return Sita: the omens were bad, the city was in danger, Rama was not to be fought. Indrajit called him a coward. Ravana answered that kinsmen are the worst enemies a man has, and that if anyone else had spoken so he would be dead. Vibhishana rose into the sky with four of his ministers, spoke his last words to his brother, and flew across the sea. In the Ramcharitmanas Ravana kicks him in open court; Valmiki has only the words.
03Refuge, and a crown
Sugriva wanted him seized as a spy. Hanuman spoke for him, and Rama gave his answer in a vow that Vaishnavas still call the charama shloka of the Ramayana: to anyone who comes even once and says, I am yours, I give freedom from fear. Rama had him anointed king of Lanka with sea water that same day, before a single battle. Vibhishana knew Lanka’s defences and its secrets; it was he who led Lakshmana to the Nikumbhila grove to stop Indrajit’s yajna. After the war he was crowned in Lanka and gave Rama the Pushpaka to fly home.
The Srirangam tradition holds that he was carrying the Ranganatha vimana to Lanka when he set it down on the Kaveri, where it stays.
Famous verses
सकृदेव प्रपन्नाय तवास्मीति च याचते। अभयं सर्वभूतेभ्यो ददाम्येतद् व्रतं मम॥
Rama’s vow on Vibhishana’s coming: to one who surrenders even once and asks, saying ‘I am yours’, I give freedom from fear of all beings. This is my vow.Valmiki Ramayana, Yuddha Kanda 18.33