Mars

Mars is the father of the Roman people. Even if the great Jupiter is superior to him, we particularly love this god because he was the father of the twins Romulus and Remus, the founders of the City. He embodies all of the qualities that a Roman man considers desirable: strength, warlike spirit, and love for battle. In Achaia he's identified with Ares, but the Roman Mars is a more careful and disciplined commander. He's the god that inspires clever battle plans to the generals and that arrays the troops in an orderly manner on the field, as in the case of the Roman legions. THe Roman Mars loves war, but he considers it a means to obtain or keep the peace. For us Romans, Mars is also god of fertility. Together with his companion, the goddess Venus, he embodies the masculine generating principle, of which she is the female counterpart. The god Mars is beloved in several Celtic and Germanic regions of the Empire as well, where he's identified with various local deities: Cariocecus, Iberian god of war, Belatucadrus and Cocidius, Brittanic gods of the area around Hadrian's Wall, Lenus, the Germanic god of the Treveri people, and many more. He's usually portrayed as a muscular and regal young man, sometimes in athletic nudity and other times with decorated armor, with his head covered by a helm and a spear in his hand.

Mars appears to be a deity that predates the Founding, or even Aeneas' arrival on the shores of Latium. His oldest inscriptions label him a god of agriculture and fertility.
-Merius