The Anti-Marleyan Volunteers were a group of soldiers who previously served in the Marleyan military, but decided to join Zeke Yeager in order to free the Eldians before the activation of the Rumbling.
The Anti-Marleyan Volunteers started off as a loose collection of rebels organized by Yelena. The members largely composed of people from different nationalities that had seen their homeland being conquered by Marley. After being forced afterwards to join the Marleyan forces and to fight for the country that oppressed them, they grouped together to try to take down Marley and secure their freedom.
During the early stages of the Marley Mid-East War In 851, a Marleyan ship arrives at Paradis Island and is promptly captured and beached by Eren Yeager's Titan form. They are confronted by Hange Zoë, offering to negotiate with them. When her commanding officer refuses to listen, Yelena promptly kills him and, along with Onyankopon, accepts Hange's offer to talk.
History: The Anti-Marleyan Volunteers started off as a loose collection of rebels organized by Yelena. The members largely composed of people from different nationalities that had seen their homeland being conquered by Marley.
Anti-Marleyan Volunteers in the story: During the early stages of the Marley Mid-East War In 851, a Marleyan ship arrives at Paradis Island and is promptly captured and beached by Eren Yeager's Titan form. They are confronted by Hange Zoë, offering to negotiate with them. When her commanding officer refuses to listen, Yelena promptly kills him and, along with Onyankopon, accepts Hange's offer to talk.
Source: Attack on Titan Wiki, available under CC BY-SA 3.0.