Though Cardassian Sekdain Istep (Ilojan transliteration: Sekdayn Istep) officially holds the rank of dalin, the chief medical officer of the CUW Trager is best known to the crew as Doctor. His role in the Thirteenth Order rebellion has made him, like his colleagues on the Sherouk, Romac, and Ghiletz, one of the most experienced Cardassian physicians in the Guard in treating non-Cardassian for a variety of illnesses. (This excludes any interrogators with medical training who may have multispecies experience.) Istep took his work very seriously, regardless of the species of the patient. (Star Trek: Sigils and Unions--"Shared Practices")
- In the Star Trek: Sigils and Unions continuity, Istep's rank places him directly under the ship's XO and chief engineer in seniority.
In 2375, Dr. Istep treated the wounds if a number of Starfleet prisoners captured at AR-558, including Lieutenant Commander Mike Spirodopoulos and the critically-injured Bajoran ensign Folani Jederia.
A few days later, Dr. Istep also played an integral role in a plot to destroy the Dominion forces stationed aboard the Trager: it was Istep who surgically transformed engineering noncom Mindesa Rhos into the likeness of the Trager's Vorta representative, Arawil. He was also involved in arranging cryostorage in which to place the Vorta, and presumably also in synthesizing tainted ketracel white for Rhos to administer the Jem'Hadar. (Star Trek: Sigils and Unions--The Thirteenth Order)
He often slept in a cot in his office during crises to remain close to his patients. One of his frequent practices with patients is the traditional Cardassian bioelectric assessment--using one's own bioelectric sense to detect abnormalities in the patient--in addition to the use of modern technology. (Star Trek: Sigils and Unions--"Shared Practices")