A rakshasa supported by Ravana. But he argued that Sita should be returned to Rama, as per Ramayana Sundarakanda Sarga 37 verses 12-13. It was this old rakshasa who sent Trijata to Ashokavana to console Sita, as per Mahabharata Aranyaparva verse 56. He also stopped Ravana when he once tried to kill Sita, as per Mahabharata Aranyaparva Chapter 289 verses 28-30.
After Rama’s victory, it was Avindhya who took Sita to him, as per Mahabharata Vanaparva Chapter 291 verses 6-7.