In Indian Mythology, specifically the Ramayana, Ravana was the king of Sri Lanka, lord of the Rakshasa, and a figure of great piety and great evil. In the Classic World of Darkness, the name "Ravana" may (or may not) be used by several entities.
In Yomi Wan lies a ruined hell called Lanka, the domain of the lord of the Rakshasa, Ravana. This Yama King has fallen into deeper apathy and depression since his defeat by Hanuman, abandoning the city mostly to its own devices.
Childe of Ravnos Antediluvian
Clanbook: Ravnos Revised details the five childer of the Ravnos Progenitor. Among them is Ravana. This childe throws in his lot with demons and abandons his master, but not before possibly tempting [Ravnos] into infernalism. It is possible that after millennia, this childe became the Yama King known as Ravana.
Dracian could have been the true Ravnos Progenitor (and a Second Generation vampire). Ravana, while still a powerful Antediluvian, could be a vampire of the Third Generation, and the founder of the modern incarnation of the clan.