Denimoor was the Captain of the Venator-class Star Destroyer Tenacious during the early months of the Galactic Empire. He had previously served under then-Jedi General K'Kruhk during the Siege of Saleucami of the Clone Wars.
Commander Teron contacted Denimoor and his ship and requested that he break ranks from his assigned duty and take the Tenacious to Arkinnea, suspecting that Imperial citizens were in danger. Denimoor was reluctant to relocate from his post unless they could give proof to their superiors, but Teron hinted that some Jedi, more specifically K'Kruhk, were on the planet, prompting Denimoor to immediately order his crew to change course for Arkinnea.
Upon arrival, Denimoor confirmed Teron's suspicions as they came upon a mass grave of refugees, who were ruthlessly slaughtered by the Arkinnea Militia. The Imperial officers then arrest militia Captain Relik and his men for mass murder. Afterwards, Teron declined to return to the Tenacious, claiming he wanted to wait for the investigation team, though Denimoor correctly guessed that Teron suspected K'Kruhk to be nearby and wanted a private talk.
Upon his return to the Tenacious, Denimoor received a holocall from Lieutenant Gregg, who inquired if any Jedi were involved in the Arkinnea incident. Denimoor casually denied the existence of Jedi on Arkinnea and Gregg appeared to accept his answer.