Onyankopon is one of the former Anti-Marleyan Volunteers working under Zeke Yeager. He was one of the Marleyan soldiers on board the first survey fleet to Paradis Island after Marley's failed attack operation.
A skilled pilot, he assisted the Survey Corps in their escape from their raid on Liberio and later operated the flying boat that held the renegade Survey Corps and surviving Warriors in pursuit of Eren Yeager during the Rumbling.
Onyankopon is a dark-skinned man with black hair styled in a short crew cut. He appears to be well-built, as seen by his large arms and shoulders. He wears a military uniform of Marleyan issue with two black stripes going down the torso.
Appearance: Onyankopon is a dark-skinned man with black hair styled in a short crew cut. He appears to be well-built, as seen by his large arms and shoulders.
Personality: Onyankopon comes off as a friendly man, easily building a rapport with Hange Zoë and other members of the Survey Corps during his dealings with them. However, he also seems to have a rather serious mindset, becoming slightly perplexed by some soldiers' fixation on trivial matters during their preparations, and praising Hange for easily adapting to the technologies and ideas introduced to Paradis Island.
History: When Onyankopon's home country was taken over by Marley, he was one of many who were forcibly conscripted into the Marleyan army to serve as a soldier. Along with many of his fellow soldiers, Onyankopon was secretly taken in by Zeke Yeager, and began covertly working to help free the Eldian people as part of the Anti-Marleyan Volunteers.
Onyankopon in the story: In 851, Onyankopon is among the first survey fleet sent by Marley to Paradis Island after the operation to retrieve the Founding Titan failed. His ship is captured and breached by Eren Yeager, where he and his fellow soldiers are confronted by Hange Zoë, offering to negotiate with them. When his commanding officer refuses to listen, Onyankopon joins his fellow crew member Yelena in disarming their commanding officers and accepting Hange's offer.
Source: Attack on Titan Wiki, available under CC BY-SA 3.0.