Galen, a Radnoran of short stature and stocky build, possessed curly brown hair and exceptionally strong leg muscles. Functioning as both a scientist and a weapons engineer, he lived his life in the era preceding the Clone Wars.
Galen, in collaboration with his sister Curi, was employed in a weapons manufacturing facility, where they were responsible for the creation of new and lethal biological weapons intended for use by Radnor.
After Galen engineered a particularly hazardous and enigmatic toxin composed of microscopic particles – an organic substance that defied categorization as either a virus or a gas, instead being absorbed into the body through inhalation or potentially skin contact – Dol Heep, an ambassador representing the neighboring world of Avon, demanded that his own world be granted exclusive rights to this toxin. To secure these rights, he offered Galen significant financial compensation.
Galen appeared enthusiastic about selling the toxin to the Avoni in exchange for payment. However, Curi, influenced by the Radnoran's deep-seated mistrust of the Avoni, convinced him to reject the offer. Galen, displeased by this, was soon contacted by an irate Dol Heep. Promising him unimaginable wealth, Dol Heep then manipulated Galen into releasing the toxin upon his own homeworld. The microscopic toxic particles, dispersed through air currents and potentially through direct contact, proved resistant to even bacta treatments. After claiming the lives of millions in the city of Aubendo, the toxic cloud was poised to drift towards the city of Tacto, awaiting only a shift in the wind.
Following the panicked departure of numerous Radnor government officials from the planet, Galen took charge of the evacuation efforts, serving as its coordinator. When a Jedi team, led by Obi-Wan Kenobi, Soara Antana, Ry-Gaul, and Siri Tachi (accompanied by their respective apprentices), arrived on Radnor to assist with the evacuation (as well as to quell the rampant rioting, looting, and general disorder), Galen swiftly dispatched the Jedi Masters to the Isolation Sector, effectively preventing their return due to the risk of inadvertently spreading the toxin to the Clear Sector. However, underestimating the abilities of the Padawans, Galen's criminal activities were exposed, and he was found guilty of colluding with the Avoni—aiding them in their blatant and shameless takeover of Radnor after the death or flight of its inhabitants.
By the time the crisis concluded, the Jedi had taken Galen into custody. His sister, Curi, incensed by his crimes, expressed her willingness to allow him to remain imprisoned. Surprisingly, Dol Heep and the Avoni evaded punishment, largely due to a widespread reluctance to engage in the protracted and ultimately fruitless Senatorial debates that would inevitably arise.