Her admission to the Academy was very difficult for her, as the preexisting stigmas surrounding Orions resulted in most seeing her as little more than a pirate or thief. This made her very sensitive, and prone to frustration when anyone would associate her with stereotypes surrounding the Orions, but also incredibly eager to prove herself as a valuable crewmember. (LD: "We'll Always Have Tom Paris")
She strangely never finished the required course unit at the Academy which trains cadets to space walk, and was simply given a B grade regardless. Tendi never questioned this until much later, believing it to most likely have been a clerical error. (LD: "Terminal Provocations")
One of Tendi's early assignments was a stint at Outpost 79 prior to being transferred to the USS Cerritos in 2380, where she was assigned as a medic under Nurse Westlake. On her first day, she met Ensigns Bradward Boimler and Beckett Mariner, who gave her a tour of the ship and introduced her to Ensign Sam Rutherford. When the rage virus broke out on the Cerritos, Tendi assisted Dr. T'Ana in treating the infected, and was even ordered to manually pump Lieutenant Commander Stevens' heart with her own hands. (LD: "Second Contact")
Tendi showed a significant proficiency in genetics when she created The Dog, an artificially-created dog made from inert carbon, as a personal side project. She hand-edited The Dog's genetic sequences to make it 5% faster and 6% smarter than the average Earth canine and considered the work to be 'fun', even lying about going to the bathroom in order to use the time to edit the sequences. In addition, The Dog possessed augmented abilities lacked by the typical dog, including shape-shifting, hovering, and spitting lightning. These augmentations were at least partially due to the fact that Tendi had never encountered an actual dog. (LD: "Much Ado About Boimler")
When she was mistakenly tapped for a classified covert ops mission to Romulus, Tendi demonstrated advanced skills in unarmed combat. She stealthily incapacitated a two-man patrol with ease and took down multiple opponents face-to-face that were larger than her and armed with Romulan disruptor rifles single-handedly. (LD: "Veritas")
By 2381, T'Ana had become impressed and even a little "disturbed" at how Tendi mastered any task that was set before her. Determining that Tendi was being limited from reaching her full potential by remaining a medic, T'Ana had her transferred from Medical to senior science officer training, thus moving from sickbay to working on the bridge, doing a lot more experiments, and going on away missions. (LD: "First First Contact")
Tendi was known to be incredibly enthusiastic, and optimistic in almost everything she did. She valued her friends on the Cerritos, and took interest in any task she was given. While others paid little heed for her positive nature, it very rarely ever bothered her, and only made her push herself even harder to do a good job at any given task. She was slow to anger, incredibly patient, and very rarely let others affect this attitude. She also valued the happiness of her friends over that of her own, though this indirectly made her hesitant to talk about herself much.
She was good at her duties in sickbay, but Dr. T'Ana noted that more often than not, she was not very assertive, and often let her crewmates walk over her. However, T'Ana was also impressed by Tendi's prowess for the job, and when she showed more confidence, she commended her for it. (LD: "Mugato, Gumato") Tendi considers archival cataloguing and hand-editing DNA to be highly enjoyable, tasks which others might find to be tedious.
While she was better known for her enthusiasm on the job, she was also quite sensitive when it came to stereotypes on Orions, but was also genuinely uncomfortable with the aggressive aspects of her native culture, which clashed with her personality. Her discomfort was a key reason for her eventual entry into Starfleet, and she did her best to distance herself from her connection with Orion culture. When it was brought up, she was noticeably uncomfortable with it and hesitant to talk about it. (LD: "Crisis Point", "We'll Always Have Tom Paris")
Tendi was fond of listening to Klingon acid punk rock music and bands of the genre, such as Gik'Tal, having commented on why anyone would wish to listen to Klingonese unless it was "punky or acidic". She kept a personal collection of music files that included cover art that could be viewed when played back on a PADD. (LD: "We'll Always Have Tom Paris")
Tendi loved archival cataloguing and liked to talk about it all the time. In somewhat of the same vein, she also found hand-editing DNA to be fun. (LD: "Terminal Provocations", "Much Ado About Boimler")
D'Vana Tendi was quite fond of fellow ensign Sam Rutherford, with him being one of her first close friends on the Cerritos. When passing by the Trivoli pulsar, Rutherford attempted to switch jobs on the Cerritos so that he could watch the pulsar with her, and not be busy with maintenance in the ship's Jefferies tubes. However, when this didn't work out for him, Tendi offered instead to watch the pulsar with him on a PADD while he worked in the Jefferies tubes. (LD: "Envoys")
After Rutherford was seriously injured in a conflict with the Pakleds, which resulted in the loss of his cybernetic implant, Tendi stayed by his side, and often read engineering manuals to him while he was unconscious. His injury affected his memory, and he did not remember who Tendi was when he woke up. Despite this handicap, Tendi was simply excited, as she believed that they would both be able to become best friends again. (LD: "No Small Parts")
For a short time Tendi became obsessed with Lieutenant O'Connor's spiritual ascension. She eventually deemed themselves as "best friends" and kissed before O'Connor completed his ascension process. (LD: "Moist Vessel")
"Ensign D'Vana Tendi, reporting for duty. I'm a transfer from Outpost 79."
"Deck 4. Follow the yellow line. Take the turbolift all the way down."
"Thank you so much! And can I just say that I'm really honored to be—"
"Keep it moving, lower decks. Next!"
"Still uh, happy to be here?"
"Are you kidding? I got to hold a heart!"
"Tendi, how long will it take to repair a biobed?"
"Oh, that would take about five... hours."
"Excuse me? That's great!"
- LD: Every episode
Tendi is voiced by Noël Wells.
In developing the characters for Lower Decks, Mike McMahan described all four leads in an 10 August 2020 TrekMovie.com interview as a combination of other Star Trek characters, parts of himself, and people in his life. Tendi developed from a suggestion by Secret Hideout that the first episode feature a character's first day on the ship. From there, McMahan took to Tendi as a character that was "all silver lining," relating how he would act on a starship. Tendi was further described as "that voice of enthusiasm... who just wants to know everything and wants to consume all things about the ship and learn and grow... who we will also watch grow throughout the series." 
Tendi appears as a duty officer in Star Trek Online.