Certoss Ajahlan was a class M planet and homeworld of the humanoid Certoss. The planet was ruled by a unified government. (TOS novel: From History's Shadow) Certoss Ajahlan had been a secondary participant in the Temporal Cold War. (DTI eBook: The Collectors)
The Certoss were aggressive in the past but the history of Certoss Ajahlan was peaceful.
In 2267, first contact occurred between the Certoss and the United Federation of Planets when the Starfleet starship USS Endeavour approached the world as part of the Federation's effort to explore the Taurus Reach. (TOS novel: From History's Shadow)
In an alternate timeline where Certoss Ajahlan was a target in the Temporal Cold War, an unidentified uptime faction influenced Certoss history, causing the planet's natives to be more warlike. Wars with the Tandarans on one side and the Humans and Vulcans on the other risked the very survival of Certoss Ajahlan.
Circa 2358, the Certoss rendered Tandaran Prime uninhabitable and almost wiped out the Tandaran species, to prevent their homeworld from suffering the same fate. Eighty years later, the Certoss dispatched a team of field agents to Earth's 20th century to destroy Humanity before they could take to the stars and threaten the Certoss. Until this timeline ceased, the Certoss suffered from constant war. (TOS novel: From History's Shadow) The end of this timeline resulted in Certoss Ajahlan never being involved in the Temporal Cold War. (DTI eBook: The Collectors)