Valtane was the bunk-mate of Ensign Tuvok in 2293. They worked during the gamma shift and shared common quarters with two other gamma shift officers, on Deck 7. As an eager young officer, Valtane expressed both approval and surprise regarding Captain Sulu's recklessness in attempting to rescue Captain Kirk and Dr. McCoy from Rura Penthe. When Tuvok expressed his negative outlook on Humans, Valtane did not take any personal offense and at the end of the conversation merely remarked that Tuvok's determination to resign his commission in the future would be "his loss".
Following Captain Sulu's abortive attempt to rescue Kirk and McCoy, the Excelsior came under attack while attempting to enter Klingon space. Gravely injured during the attack, Valtane, while in a state of clinical death, unwittingly transferred a memory virus to his attendant crewmate Tuvok. (VOY: "Flashback")
Background information Edit
This character had no first name in Star Trek VI: The Undiscovered Country; it wasn't established as "Dmitri" until "Flashback". The name wasn't included in the first draft of the episode's script, but was in the final draft of that teleplay.
In the script of "Flashback" (both the first and final draft of the teleplay), the adult Valtane was consistently referred to as a lieutenant.
Peter David's novel The Captain's Daughter stated that Valtane was the Excelsior's first officer; the novelization of Star Trek VI also stated this. However, DC Comics had a story arc, collected in Tests of Courage, by Howard Weinstein in their second TOS volume that instead had Rand as first officer.