He served as the main antagonist in the Season 9 episode "Rabid".
Like other Kandorians before him, Coats donated a blood sample into an Orb created by Jor-El who had been tasked by the Ruling Council to preserve the Kryptonian race by fulfilling Rao's prophecy.
Coats later died in the explosion of Kandor.
Coats was created when the Orb opened releasing clones of the individuals whose DNA has been stored inside of it. Coats later met with the Kandorian Army at the Luthor Mansion who placed Zod and Tess Mercer on trial.
When they began questioning Zod and Tess, Zod used his natural leadership skills to gain their trust and they left their temporary base, the Luthor Mansion leaving no evidence and with Tess hunting them down.
Coats began to blend into Earth society, acquiring a job as a doctor at Metropolis General Hospital where he began researching his suspicions that Jor-El came to Earth with them, after seeing the House of El symbol all over Metropolis.
In order to learn more and draw the hero out, Coats developed an airborne virus which turned humans into ravenous zombies that was spread over Metropolis. The virus was designed to induce sleep, during which it germinates and takes over the infected person.
Tess became infected and was taken to Metropolis General Hospital where Clark Kent and Lois Lane paid a visit. They overheard Dr. Coats, who was posing as a Disease Control Agency specialist, discussed the fact that Tess was having hallucinations caused by a virus and went into her room to investigate.
When it was revealed that she had transformed into a zombie, Tess attacked Lois and had to be restrained by Clark until Coats sedated her. Clark took a blood sample from Tess for Chloe Sullivan, to analyzed it and brought up the security files from the manor and found the zombies.
Emil Hamilton speculated that the virus caused hyper-aggression, and Clark super-sped him to the hospital to talk to Coats. When a doctor informed Coats that Tess was brought from the Daily Planet, Clark realized that Lois was in danger.
The virus quickly spread from the hospital to the city and in just a few hours, the streets of Metropolis were deserted. Emil then recognized that the base enzyme was similar to that of Davis Bloome.
Because Davis was Kryptonian, his enzyme was as well, so Chloe and Emil used Clark's blood to make the antidote for the zombie virus. They flew to the Metropolis water supplies and distributed the antidote, then seeded it into the clouds in the form of rain. The antidote cured the infected zombies, as well as Lois who was recently infected.
Coats later went to Zod, who said that Coats had become reckless in unleashing the virus. It could have endangered the lives of his soldiers and other separated survivors. Coats then revealed that the antidote was made from Kryptonian blood and gave Zod a paper with the Mark of El, telling Zod that the symbol appeared all over Metropolis from someone called "The Blur."
Zod immediately believed that The Blur was Jor-El. Coats gave Zod the blood sample from the antidote and explained that they could track it. Zod told Coats to kneel and then beheaded him for his insubordination with a katana.