Background and early life
At some point before 2038, Eva joined the Seraphites and lived on the island a short boat ride from Seattle. She eventually became a soldier a joined a brigade to fight against the Washington Liberation Front. Her cheeks were cut per the Seraphites' initiation process, leading her to complain her cheeks burned for two weeks.
Events of The Last of Us Part II
In April, 2038, Eva was selected to take part in an assault against the WLF. That night, she snuck out and met her friend at the tannery, where they discussed the process of initiation when teenagers among the Seraphites have their cheeks cut to officially become a Seraphite soldier. She warned her friend to not show weakness to the elders. The two stayed together that night, watching a fire. Eva then asked her friend if they had been promised to another Seraphite yet. Before she let them answer, however, she kissed their cheek then ran back to her camp.
The next day, Eva left with her brigade. The group not returning the next day, which worried her friend.