In the fifth movie, Artemis believes she is a god, and a superior being, so, she naturally has a right to govern the humans with no duties, and the human duties are just follow the gods with rights give by them. Artemis is encouraged to take the Earth rule to her, because the manner that Athena rules, is not most accepted by the Olympus, and 3 Olympic gods arrest 12 gold saints (Aiolos is not arrested, but Shion is) and Artemis ask for his sister the rule in Sekai. The angels of Olympus (service any Olympic god) will help Artemis, and Athena saints that did not commit grave sins, will help her too. Artemis became the goddess of Sekai and start the Armageddon to create her new world, and Athena must just see in silence. Athenaasks to Artemis to slow down the Armageddon in exchange of her blood. Now, the five saints of Athena like Seiya, were fired becausethey are sinners and don't have a god to protect.
Seiya arrives in the Artemis temple in the Earth, and Athena tries to kill him, because she must accept the gods desire. But, she just feigns kill Seiya; she removes Hades sword from his hearth, and Seiya gets up and try to kill Artemis. Apollo arrives there to resolve(with her silliness) what Artemis failed to do.
She refuses help Athena to help Seiya, because she fears Zeus remove the divinity of Athena after various rebellions against Olympicgods. Artemis, unlike the movie, cares for her sister.