Kattell was a Cardassian woman fabricated by the Cardassian spy Seska.
In 2371, The Doctor discovered that Seska's blood chemistry was not consistent with that of a Bajoran. She claimed to have survived a childhood bout of Orkett's disease due to a bone marrow transplant from a sympathetic Cardassian woman, named Kattell, who she claimed they could ask themselves if they ever returned home.
Her claims were ultimately proven untrue by expert testimony from The Doctor. (VOY: "State of Flux")
This character was only mentioned in dialogue.