Eagle Marin, is the woman saint of Eagle in the XX Century.
In the young age, Marin was a serious girl, but and mature too. She is sage, and always helps Seiya, making her seem even stronger than he and many other saints.
According the fifth movie, Marin and Tohma was brothers, but in his childhood, Marin and he was separeted, and only a bell was the reference point between they, because each one keeps a bell.
As a Saint
Marin goes to Greece to search Tohma, and became a Saint; according Asterion, Marin lost his memory whe put his mask. Marin after, suspects the pope is not Shion, but a traitor and Athena is not in the Sanctuary.
Marin saved Aiolia of Chronos servants, and after, Aiolia saves Marin of a giga. Aiolia become her best friend.
When Seiya arrives in the Sanctuary, he was give to Marin tutelage, and Marin teached Seiya about the cosmo in the Saint training. Seiya become a friend of Marin (she is of Japan, like him) and when gots his cloth, Shaina (her rival; she is a strong woman saint and his disciple [Cassios] lost the Pegasus cloth to a japanese; she don't like Marin because she is Japanese too probably) try kill him, and Marin takes him to escape of the Sanctuary.
In the anime, when Seiya come back to the Sanctuary, Marin stop Shaina attacks, and allow Seiya cross the local.
She was sent to kill Seiya with Misty, Moses, Asterion and Babel, but tell to them the wrong location of the bronze saints, and they kill the Black Saints. But Misty finds the true Seiya, and because this, Marin feigns to kill him; Misty perceives this, and wait Marin (supect of make a betrayal) leaves the place, and pulls Seiya of his grave, to really kill him.
Moses, Asterion and Marin comes back to that place, and Asterion read her thoughts and discovers her betrayal. He uses she to atract Seiya, as a hostage, but after Seiya defeat, Marin scape (because don't have another way, because Seiya was defeated) of the sea, and kills Asterion. She become a rebel after this, and never returned to the Sanctuary normally.
She only have gone to the Sanctuary, to climbs Star Hill, where was attacked by Jaki (the pope ordered it). In the top of Star Hill, Marin discover the body of the true pope, and goes to the Pisces Temple helps Seiya. Seiya after the battle against Moses, thought Marin is his lost sister. Shaina became her best friend in that time.
After this, in the manga, Marin disappears again.
Marin talk with Aldebaran about his defeat to Syd, and Aldebaran tells to her, that blocked all his attacks, but something hitted him. Later, Marin goes to Asgard after discover the evil twin of Syd (Bud), but Alberich imprisiones her in a ametist, and Seiya goes fight against Syd before Marin wake up. But, she tells to Shaina about Bud, and disappears later.
Kasa gets Marin apparence to cheats Seiya, and shows Marin true faces.
Marin finds Seika (she disappeared since Asgard arc to tries to find her),Seiya true sister, after search near of the Sanctuary. After, she, with Kiki, takes Seika to the Sanctuary where is Shaina, Jabu, Ichi, Nachi, Ban and Geki; all they protects Seika of Thanatos attack.
Fifth Movie and Next Dimension
In the fifth movie, she helps Seiya to fight against Tohma, and she discovers that him is his brother. He don't accept loves she, but in the final, she cares of him after Artemis accidentally hurts him.
In Next Dimension, she protects Seiya of Tohma attacks and with Shaina, discover the Ophiucus Temple.
Marin trains Shoko, Xiaoling and Mii to became strong saints.