Life as an adventurer
Born as the only child to a wealthy farmer in Megaris, and named after Odysseus, Odessa had grown up in comfort, save for a heart with a wanderlust.
After she'd grown up enough, Odessa embarked on a journey to reach Odysseus' home island of Ithaka, in order to learn more about her ancestor. However, when she reached the island, she was caught by bandits, and locked up. Fortunately for her, the Kephallonian Kassandra had come to the island, too, and freed her. Together, they explored Odysseus' Palace. Disappointed with what she found, she decided to return to her home in Megaris.
Return to Megaris
Upon her return, Odessa found her father faring poorly. Stuck with taking care of him, she also clashed with the leader of Megaris, who sought to obtain her father's estate. The leader orchestrated a number of suitors to court Odessa, including Palermon and Praxis. In response, Odessa hired the mercenary Xenokles the Hyena to protect her farm from the harassers, and the mercenary died in this line of duty. At one point, Odessa also was targeted by The Master, a member of the Eyes of Kosmos branch of the Cult of Kosmos.
Sometime later, Odessa met Kassandra again and confided in her on her father's condition, requesting her help to gather some herbs in the valley. While Kassandra was away, another attack was launched against Odessa's farm. With the help of the returned Kassandra, Odessa was able to beat back the bandits. As revealed by a letter on one of the attackers, they had been sent by the leader of Megaris.
In an attempt to end the harassment and threats on her life, Odessa requested Kassandra to infiltrate the Leader House and uncover what she could find. Having recovered enough information, Kassandra returned to Odessa to report her findings.
Behind the scenes
In Assassin's Creed: Odyssey, Odessa is a character which can be romanced. She can also be recruited to join the Adrestia as a lieutenant upon the completion of "The True Story". Completing The True Story regardless of outcome grants Kassandra her bow.