Next, Ravana vowed to conquer Yama, God of Death, so he rode his chariot south towards the Land of the Dead.
Yama's soldiers attacked Ravana, but Ravana destroyed them all.
Yama himself then rode forth to face Ravana, and Ravana's soldiers fled in terror.
Alone on the battlefield, Ravana and Yama fought fiercely for seven days and nights. Then, as Yama was about to strike Ravana with the Death-Hammer, Brahma appeared.
"Halt!" Brahma shouted. "I gave Ravana my blessing; no deva can kill him, not even the God of Death."
So Yama vanished, and Ravana declared himself Conqueror of Death.
Inspired by: The Ramayana (Uttara Kanda, 21-22).
Notes: The original text is full of great details about this battle between Yama and Ravana.