In a lot of Greek Myths, Ares is kind of a childish jobber but if you take into account Roman myth, he basically goes through a redemption arc and become the main god of the Pantheon.
It's because a lot of myth that were passed down to us are from Athenians during an era where their influence was peaking while Sparta, their rival, were kinda falling off and then you got Rome, who had Ares / Mars as their city's deity who kinda took over everything and thus put their own patron god above others.
So it make sense for a world made to fill in the gaps in a Greek Myth inspired setting to place him as second in terms of pure power.
He is below Athena, who is below the trio.
It's to be noted that Athena outdoes Ares mostly thanks to her wisdom rather than in raw power. The only God who is consistently mentioned to overpower the others is Zeus.