Baro Ki'Teer makes appearances within the Concourse section of the Tenno Relays, although his presence is not constant; he makes appearances every two weeks, and is only available for trading for up to 48 hours after surfacing before he disappears once again. A countdown timer is displayed on the two Void Trader Kiosks found in the Concourse section of the relays, indicating the time until Baro Ki'Teer will next become available for trading. While the Void Trader is present on a relay, the countdown timer on these kiosks changes to display the time remaining until he leaves.
24 hours prior to his arrival, an icon can be seen on the Star Chart near the relay where the Void Trader will be during his next visit, which will slowly move along the path to the relay during this period. Once he has arrived, players will receive a message from Baro Ki’Teer in their inbox, notifying them as to which relay and on what planet he can be found.
Almost every item sold by Baro Ki'Teer requires Ducats as payment, an unique currency that can only be acquired by exchanging Prime parts at one of two of the Ducat Kiosks in the Relays. Prime weapon parts, Prime Warframe components, and Prime Blueprints can be exchanged, with rarer parts being worth more Ducats.
Baro Ki'Teer sells a limited stock of unique items from the Void. His selection of stocks changes with each appearance, making his items limited in availability.
Little is known about Baro Ki'Teer aside from his conceited attitude, to the extent where he looks down on Tenno without Prime gear. In spite of this, Baro Ki'Teer has shown a willingness to aid the Tenno for a price, as he was the one who provided the data to construct the Archwings. Much of his dialogue heralding his arrival suggests that he has access to the Void and has entered it to locate rare treasures, an impressive feat indeed, considering the rarity of some of the items suggests a great deal of risk.
Referring to himself as a "Mystery Associate", Baro Ki'Teer anonymously contacts the Tenno, offering his assistance to combat the threat of the Balor Fomorians. He explains that he will give them the technology needed to defeat the Fomorians (as well as additional rewards for exceptional performance), but in exchange the Tenno must harvest Cryotic, which (at the time) can only be excavated on certain planets of the Solar System. As the Tenno collect Cryotic and get additional rewards, Baro Ki'Teer reveals that he needs the Cryotic to preserve the Martian Oasis Jellyfish, a delicacy that spoils easily during transport.
In a series of deals following the event, Darvo reveals Baro Ki'Teer's identity to the Tenno, commenting that he does this to make him appear mysterious to his clients. He reveals that he decided to sample the Jellyfish, exchanging a crate full of Prime blueprints and two Argon Crystals to do so, only for his throat to swell up for a few days as a result. This suggests that Darvo revealed Baro Ki'Teer's identity solely to spite him.
Shortly after the events of Operation Cryotic Front, the opening message for Operation: Gate Crash reveals that Baro Ki'Teer gave the Tenno a datamass containing information about an ancient piece of technology; the Archwing, the centerpiece of the Tenno's plans to defeat Vay Hek's Balor Fomorians. Whether or not Baro Ki'Teer was involved further in this operation is left unsaid.
Baro Ki'Teer requests the Tenno's assistance in raiding a temple located on Mars in search of treasure, derisively calling its previous colonizers (prior to Grineer takeover) "Sky Worshippers". As the Tenno explore the temple, a mysterious female voice begins narrating the legend of "Inaros the God King" who protected the Sky Worshippers from "Golden Skymen" and the Infestation, which begins to unnerve the Void Trader. The Tenno collect a Sacred Urn from the Temple, and Baro Ki'Teer urges them to fulfill the Urn's inscriptions to uncover more of the Temple's secrets.
As the Tenno explore further into the temple Ki'Teer becomes increasingly distressed by the narrator's story. Towards the end of the quest it is revealed that Baro Ki'Teer originated from Mars, and that the narrator's voice belonged to his late mother. Baro Ki'Teer was the sole survivor of a Grineer attack on his village, and despite praying to Inaros, the God King never arrived, resulting in his resentment towards his former home. At peace with his past, Baro Ki'Teer thanks the Tenno, remarking that the God King will rise again.
- Baro was one of the people who lived on Mars before the Grineer exterminated the population. His mother was killed while he hid, and he was apparently the only survivor.
- The Ducats he uses as currency are named after a real life currency made of gold or silver used from medieval times until the 20th century.
- Baro Ki'Teer will treat players wearing any prime weapons or Warframe with respect, occasionally praising them to be the "one with good taste".
- Baro Ki'Teer has a very large amount of voice lines, and will often comment on the player's equipment. When leaving his shop interface without buying something, and you do not have a prime item equipped, he will often comment about how the player has something to work towards, implying the items are out of their reach, or recommend Darvo as an alternative, implying that he finds Darvo's merchandise is at a lower tier than his.
- The in-game timer is inexact, reflecting the time until Baro Ki'Teer arrives give or take one minute.
- When Baro Ki'Teer arrives in a relay, he appears in a blue flash with small particles emitted, similar to many Tenno idles and abilities.
- During Tennocon 2017, Baro Ki'Teer arrived in a special relay accessible by anybody who purchased a ticket. His inventory contained everything he had ever sold up to July 8th, 2017.