The Lupari, singular Lupar, were a humanoid race that resembled Earth dogs. They were warriors with a great sense of honour. They were species-bonded with humanity, meaning each human had a Lupar tasked to protect them. On Halloween 2021, seven billion Lupari ships approached Earth to protect it from the Flux
The Thirteenth Doctor and Yaz tried to track down Karvanista for information on the Division, though the Doctor would not tell Yaz the true reason. After much annoyance, Karvanista trapped the two hanging by a gravity bar over an ocean of acid, though they managed to escape.
As every Lupar was tasked to save a human from the Flux on Halloween, Karvanista left with his fleet to rescue his designated human, Dan Lewis. A wave of temporal energy caused his ship to arrive a few hours before the rest of the fleet. Karvanista broke into Dan's house and kidnapped him without any explanation. He placed him in an electrified holding cell on his ship and departed into space.
After Karvanista left in his ship with Dan, the Doctor and Yaz traced his ship to Dan's house. They escaped his booby traps, but the Doctor was still able to gather enough information using her sonic screwdriver to trace Karvanista's ship in space, as well as uncover seven billion other Lupari ships heading towards Earth.
Thinking this was an invasion, the Doctor materialised the TARDIS on Karvanista's ship to confront him. She deactivated the ship's power while Yaz freed Dan. The Doctor told him she was there to ask about the Division, but first she needed to know why the Lupari were invading Earth. After noticing a signal that still reached his ship, Karvanista frustratedly explained the Lupari were bonded to humans and they were arriving to rescue them from the Flux. Before the Doctor could inquire further, the ship's power restored as well as Karvanista's weapon, so he chased them. The Doctor, Yaz and Dan escaped into the TARDIS. After experiencing a vision of Swarm, the Doctor observed the Flux approaching from her TARDIS and told Karvanista to instruct the fleet to create a barrier around the Earth, protecting it. (TV: The Halloween Apocalypse)
Karvanista was gruff and found humans, especially Dan, to be annoying. He found it insulting to his species to be compared to a dog.