Ravana was the leader of the Infinite Suns. He was a rakshasa of great power who's infernal army threatened the security of the ancient Dans of Danasia. Ruling from the Spire of Endless Day in the Great Gash, his army swept the countryside slaying any who brandished a weapon against them, their ultimate goal, to feed Ravana's insatiable ego. Ravana had an insatiable appetite for fine food, beautiful women (of all races) and magical items. He often appeared to people who viewed him as a hedonistic simpleton, though this was a ruse to disguise the fiends malicious intellect.
The rakshasa lord was finally defeated, not by an army, but by a simple farm girl, brandishing the 6 demon bag. His infernal army vanished moments after he did, being forced out of the prime dimension.
In the 5th age, Ravana was released from the bag and became a uneasy ally to a party of adventurers as they attempted to defeat the Hand of Thrym.
He was the wielder of the incomplete Sun's Touch Gada, allowing him to move armies to anywhere the sun can see in the blink of an eye.
Ravana's unique lineage offers him incredible powers, namely power over his djinni father's vessel, also known as Kaseraksa, City in a Bottle. If killed, he and his kind will reform within the bottle. So long as the bottle existed, Ravana and his minions could not truly be killed.
In 158V the same party that released him from the 6 Demon Bag destroyed the bottle containing Kaseraksa. This released the city back into the material world and severely crippled Ravana's power. In fear of his life, Ravana retreated to an unknown plane.