Jerso

Jerso (also spelled Jelso) is a military operative under the command of Solf J. Kimblee. He was used as a test subject in military experiments and is now a human chimera capable of transforming into a strange, toad-like creature. He is partnered with Zampano.

Working for Kimblee
While being part of the military, Jerso and his partner Zampano were Kimblee's body guards. They confront Scar and are easily deafeted by him and the Elric Brothers. Before Major Miles has a chance to execute them though, Alphonse convinces them to come with them on the promise that they may be able to get back their original bodies. They escape in the old mine shaft with Al, Scar, Dr. Marcoh, May Chan, and Yoki.

Confronting Envy
While in a small Ishvalan refugee camp, the group confronts Envy after Zampano tips him off to their location. Zampano actually tricks Envy into coming there to fight them, and plays a part in battle against the homunculus. May's long range alchemy, his and Zampano's attacks, and Marcoh's Philosopher's Stone are what ultimately defeats Envy.

In Central
After May is supposed to return to Xing with a weakened Envy, the rest of the group travels toward Central and meets up with Edward, Darius, Heinkel, Lan Fan, Fu and Hohenheim. They aid in Mustang's invasion of Central, infiltrating the bowels of the city and capturing the Gold-Toothed Doctor with his spit. He is then wounded by Pride and drops the Doctor to the ground as he falls. He is incapacitated for the rest of the battle due to his injuries. He is last seen with Zampano in a cafe', discussing different methods to get their bodies back, and are about to set off to Xing with Alphonse as his body guards.

Abilities
Jerso is a human based chimera and can transform into a large toad-like monster. While in this form, he can spit an extremely sticky saliva that can immobilize his targets and he can also move quite fast for his size.