Yh’ahni was a Starfleet officer and chief of security aboard the USS Cantabrian from late 2372 until 2373, and later aboard the USS Cantabrian-A from 2374 until late 2376.
In 2345, military members of Yh’ahni’s race attacked the Federation starship Nguyen Dinh Van and his wife Dr. Nguyen Thi Xuan-Hong were crewmembers aboard. The Nguyens and several others escaped to a derelict Starfleet starship (as their ship was destroyed), where they found a pregnant woman (also of Yh’ahni’s race). Mortally wounded, she begged the Nguyens to help her give birth then take the child to safety.
After the alien gave birth to her child, she told Dr. Nguyen she wanted her daughter to be named Yh’ahni. The alien then passed away without explaining why the military of her own race was attacking her and the others, or how she got aboard the derelict ship. Yh’ahni was born on 15 March 2345.
The survivors somehow defeated the aliens and made a dash for Federation space in whatever craft they could find or salvage or gain safe passage on. Yh’ahni recalled growing up experiencing many different cultures and societies on their way back to the Federation.
Yh’ahni entered Starfleet Academy in 2362 and graduated in 2366.
A part of her realized the reason she wanted to explore the stars was to look for where she came from and perhaps find a piece of herself once she discovered her race. As of 2372, she had not realized that dream yet.
Yh’ahni served aboard the USS Marsh as chief of security under the command of Captain Rangi Manawatu. During this time, she grew familiar with the various races living near and around the Typhon Expanse, including the Trookanians and Straulausians.
In 2372, on a routine stop at Starbase Expanse 4, a Myhr’an attack destroyed the Marsh and obliterated both the ground and orbital bases. Yh’ahni, along with others, managed to survive by being on a cave expedition led by Ambrose Wong kilometers from the starbase. An away team from the Cantabrian rescued them. (“Catalyst, Part One“)
Aboard the Starship Cantabrian
Captain Noah Wrightson was impressed by Yh’ahni’s investigative and observational abilities that he asked her to stay aboard as a member of the Cantabrian‘s crew. Yh’ahni, keen at the opportunity even if it meant a reduction in position as a subordinate of Cantabrian security chief Ulitania Jonar, accepted. (“Catalyst, Part Two“)
At Starbase Expanse 7, Yh’ahni discovered, through a trader, the possibility of survivors from the Marsh, SE4 and other Starfleet ships and bases attacked by the Myhr’an. She convinced Wrightson to allow her to accompany the trader to the Myhr’an internment camp in order to free the survivors, including the family of her fellow crew member (whom she promised she would keep safe in the event of his death). Upon arrival, however, she found the trader had double-crossed her, attempting to exchange her for the release of his family. Finding out the duplicity of the Myhr’an, the trader reneged on his deal, ramming his ship into a Myhr’an battle cruiser attacking the Cantabrian on the proviso Yh’ahni ensured his family’s evacuation and safe passage.
Yh’ahni insisted on remaining behind until the last survivors were beamed up and was mentally prepared to remain behind when the Cantabrian fell under heavy fire by two more Myhr’an battle cruisers. Preparing the other remaining survivors to take on any Myhr’an in hand-to-hand combat, Yh’ahni and the others were beamed aboard the Cantabrian when the USS Aotearoa arrived, laying down covering fire and distracting the Myhr’an. (“Two Hit, One Stone“)
During the Renai’i boarding raids, Yh’ahni confronted Renai’i soldiers, all of whom refused to fight her. When she continued to fight regardless, the Renai’i retreated. (“The Eagle“) This was the third time alien races avoided battling her: something the trader had alluded to her having a special status amongst her people (although he did not say who her people were). (“Two Hit, One Stone“)
Excerpt from Captain’s report
Profile by Captain Rangi Manawatu, stardate 49311.7
Yh’ahni started aboard my ship, the Marsh, as a security officer but was quickly promoted to chief of security once the position came available. Her overall security and tactical skills rival even the swiftest and highest trained Klingon’s or Breen’s. Yh’ahni seems to have the innate ability to fight, to protect herself and her shipmates, and to understand and adapt to even the most advanced and complex of situations.
In saying that, Starfleet Command, and indeed all experts in the Federation, have never encountered another member of Yh’ahni’s native race. Her DNA seems extremely complicated, more advanced than many races in the Federation. Her adopted parents, Mr. and Dr. Nguyen, found Yh’ahni aboard a listing Starfleet ship far outside the Federation while on a deep space science mission. During this mission, the Nguyens and their shipmates encountered a hostile race, responsible for the destruction of the Nguyens’ ship, the other Starfleet ship, and the death of the Nguyens’ shipmates. The majority of Yh’ahni’s childhood was spent aboard various trading vessels as the Nguyens, with their adopted daughter, made their way back to the Federation.
Yh’ahni remains one of my most valuable officers, and Starfleet Security now actively seek Yh’ahni’s tactical advice.
Anatomy and physiology
Yh’ahni stated her anatomy and physiology allowed her to adapt to various adverse conditions. It was almost anatomically impossible for her to smile as well. (“Catalyst, Part One“)