Yoki

Yoki (ヨキ) is, when first introduced, a corrupt member of the military who imposes heavy taxes on the town of Youswell, bankrupting its citizens. When the Elric brothers arrive in town, they trick Yoki into giving up ownership of the town and promptly report his actions to the military. He is stripped of his rank and lives as a homeless person on the outskirts of Central, where he meets the fugitive Scar.

Manga and 2009 anime
In the manga and 2009 anime, Yoki is forced to work for Scar under the threat of death. Though he tries to convince those they encounter that Scar is his servant, Yoki always does as Scar commands and even calls him "master". Since he has started following Scar around the country, Yoki has assumed the role of a comic relief, often having pain inflicted upon him when he tries to seem superior to others. In Chapter 93 and Episode 52, Yoki manages to hit Pride with Kimblee's car, buying Alphonse and Heinkel some much needed time to escape. His reason for doing this was because everyone else "gets all the cool parts".

While he wasn't seen during the final battle, he was later shown in a photo from years after the main story, which shows him having joined up at a circus alongside Heinkel and Darius.

2003 anime
In the 2003 anime Yoki's original appearance is largely the same, the only difference is that he has enlisted the help of an alchemist named Lyra to enforce his laws and protect him.

Later in the series, Yoki alerts the military to Scar's location, and in the subsequent raid to apprehend Scar, Yoki hopes of using Scar's arrest to be reinstated back into the military. Yoki is killed by Lust, which stirs up tension between the soldiers present and the Ishvalans until Roy Mustang steps in and uses his Flame Alchemy in a demonstration to prevent a battle.

Later when Edward arrives at the Southern slums, he is able to identify Lust as Yoki's killer from the stab wounds he sees in a few photos and is able to get the Ishvalans out of further trouble having proven they are not involved with Yoki's death.

Trivia

 * In an omake chapter, it shows Yoki opening The Gate, and Truth taking his hair as a toll.
 * In the 2009 anime, it's shown that after Yoki is discharged from the military, he has many other attempts to get back on top, some including odd jobs and a failed attempt to steal from the Armstrong family.
 * Both Yoki's Japanese and English voice actors play Bentham (Mr. 2 Bon Clay) in their respective dubs of One Piece.
 * Yoki got ranked to the 19th place in the latest popularity poll.
 * Despite appearing useless and more of the comic relief of the group, he has shown a few times that he has very useful information when the time calls for it. For example, knowing the inner workings of a mine due to his previous military position in a mining town.
 * Yoki seems to think that all his acquaintances are friends, even if they hate him, the only clear exception being the Elric brothers when he briefly wanted revenge against them for getting him ousted from the military; however even this fades away before long.