Jō Anno holds the position of Chief of the Hero Section in the Earth Defense Force's Saitama Branch. As the uncle of protagonist Retto Enjō, he recruits Retto into the HxEros team following a Censor Bug attack on Retto's childhood friend. He oversees the HxEros initiative and researches H-energy applications, employing a rational, science-focused strategy against alien threats.

His long green hair is typically secured in a ponytail. He favors an open white lab coat over a black crop vest that exposes his chest and abdomen, paired with tight black shorts and pale green shoes, a style suggesting exhibitionist tendencies.

He designs experimental technology for the HxEros team, including early "XERO suit" prototypes intended to withstand H-energy during combat. These suits resemble standard underwear and carry an unintended side effect: they continuously accumulate H-energy in the wearer, creating operational complications. He also manages Saitama Branch logistics, providing spare clothing and budget allocations to replace garments destroyed during H-energy discharges.

His primary focus remains understanding and harnessing H-energy, frequently treating field missions as data-gathering opportunities on its capabilities and limits. While his professional relationship with nephew Retto centers on defense duties, familial concern occasionally emerges, particularly regarding Retto's integration with the team.