Which brother of Ravana sided with Rama?

Vibhishana was the brother of Ravana who sided with Rama.

Unlike Ravana and the warrior Kumbhakarna, Vibhishana is portrayed as pious, thoughtful, and committed to dharma. When Ravana abducted Sita, Vibhishana repeatedly urged him to return her and avoid a disastrous war with Rama. Ravana rejected the advice and ultimately expelled him from Lanka.

Vibhishana then approached Rama, who accepted his allegiance despite his rakshasa birth and family connection to Ravana. His knowledge of Lanka’s defenses and Ravana’s forces became valuable during the conflict. In several retellings, he also reveals crucial information that helps Rama defeat Ravana.

After Ravana’s death, Rama had Vibhishana crowned king of Lanka. Kumbhakarna is a common mix-up because he was also Ravana’s brother, but he fought for Lanka out of loyalty to his family. Prahasta was Ravana’s commander, while Ahi-Ravana belongs chiefly to later or regional Ramayana traditions.