Jo Aysel is a Republican soldier initially assigned to defend important ruins. Her path crosses with Leo Conrad, Sally Land, and Buzz Cunningham during their journey, prompting her to leave her post and join their group. Despite traveling with them, she maintains her Republic military affiliation and continues fulfilling duties on its behalf. This includes claiming strategically valuable locations discovered during their travels for the Republic, contrasting Buzz Cunningham's focus on salvage rights. Recognizing the significance of Leo and Sally's mission involving the Regeneration Cubes, the Republic eventually grants her explicit permission to travel freely with the group.

She pilots a Raptoria, a smaller Zoid unsuited for direct frontal combat. Consequently, she primarily fulfills support roles during battles, effectively utilizing her standard military piloting skills for reconnaissance and tactical assistance rather than heavy engagement. She often coordinates closely with Leo Conrad in combat and affectionately refers to her Raptoria as "Rap-chan."

Her personality is characterized as bubbly and energetic. She demonstrates deep care for her comrades and forms a strong bond with her Zoid partner. She readily integrates into the main group, actively participating in their adventures and battles, such as in "The Traitorous Gatling Fox" and "Roar to the Skies! The Liger's Counterattack!!" where she fights alongside Leo, Sally, and Buzz. Her character model features a customized variation designated as the "Raptoria Jo Aysel Spec."