He was voiced by Barry Yandell.
When the Elric brothers arrive in town, they find it struggling under the strict taxes enforced by Yoki and his associates. In the manga and Brotherhood, they trick Yoki into giving up ownership of the town with a cart full of coal made to appear like gold and promptly report his actions to the military. In the 2003 anime, however, he also enforced his rule with an alchemist in training named Lyra who used her alchemy to throw off anyone who opposed him. Nevertheless, Ed managed to defeat her, resulting in Yoki being deposed and forcibly removed from the settlement.
He is stripped of his rank and lives as a homeless person on the outskirts of Central, where he meets the fugitive Scar. However, he redeems himself over the course of the series when he becomes a (sometimes useless) ally. In the end, he is revealed to be working as a circus clown.
In the 2003 anime however, he remains a homeless person who is taken in by a settlement of Ishbalans. Unfortunately, he turns them into the military and openly mocks them for calling him out for his cruel act. However, Yoki does not gloat for long as he is then murdered by Lust to stage a riot between the military and Ishbalans.