Question

Was Ravana a vegetarian?

Answer

Ravana was not a vegetarian.

As per UTTARA KANDA of Valmiki Ramayana, this is what Ravana did in king Marutta's Maheshvara yajna:

Ravana in king Marut's yajna

And then devouring the Maharshis that were present at the place of sacrifice, Ravana, satiated with their blood, again went to the earth. (English translation source)

The complete story of king Marutta's Maheshvara yajna is given here.

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