Greek war god

ARES

This deity's Roman counterpart is Mars, known for his fierce and violent nature.

The clue "Greek war god" directly points to Ares, who is the ancient Greek deity associated with war and violence. In Greek mythology, Ares is often depicted as a fierce and aggressive figure, making this a straightforward reference without any wordplay or hidden meanings. If you're familiar with Greek gods, this clue is a simple recall of his name.