10 Hade

The God of the Underworld was Kratos' toughest test outside of Zeus in God of War III, and his capacity to manipulate people's souls set him apart from the other powerful characters in the game.

9 Artemis

We have no idea what became of Artemis, since she never returned after her one appearance in the first game; she was missing from Kratos’ conquest against the gods too.  

8 Pandora

Pandora had no special abilities other than being the key to opening the box from behind the Flame of Olympus, but she ended up being the reason Kratos was ultimately successful in defeating Zeus.

7 Athena

The person who has been most steadfast in supporting Kratos is Athena, who, until God of War III, was his lone godly friend. Kratos was able to complete the duties the gods assigned him because of Athena's leadership, and she was the primary factor in his elevation to the position of God of War.

6 Atlas

Atlas’s disadvantage seemed to be that he found himself at the wrong place at the wrong time, as the Titan was pinned to the Earth and forced to hold it up for eternity because he was caught off guard by Kratos.  

5 Freya

Kratos had seen a lot on his journey from the Greek to the Norse realm, but the upcoming God of War game may reveal Freya's true abilities, even though she won't be an ally.

4 Poseidon

Though he proved to be less difficult to defeat than we had anticipated, Poseidon's gift to Kratos in God of War remained the creation of his anger.

3 Gaia

In God of War II, Gaia's intervention saved Kratos from an eternity of agony in the Underworld. Although she used Kratos as a pawn, Gaia was the one who planned the Titans' entrance into the present; as a result of her, he was able to complete his task of destroying the Sisters of Fate.

2 Ares

Kratos’ original boss was a very powerful god indeed, but was eliminated first in the series because he would’ve been a huge hindrance in Kratos’ way otherwise. 

1 Zeus

Zeus wasn't an ally for us for more than a single game, but he was a lot more helpful than most people understand. The fact that Zeus was the one who rescued Kratos from the Underworld in God of War is still a secret, and Kratos was given the job of locating Pandora's Box—the item that bestowed godly powers—as a result of Zeus's directive.