The relationships of Kallus.
- Main article: Garazeb Orrelios
- “You, Lasat! Face me!!'”
- ―Agent Kallus challenging Zeb[src]
Kallus took a sadistic interest in Zeb, calling him out to a Bo-rifle duel, wielding the one he claimed to have taken from a fallen Lasat Honor Guard as a trophy, mocking his fear of the disrupters, and cruelly admitted to being the one who ordered their use against the Lasats, bringing the species to near extinction. In doing so, he made Zeb a personal enemy.
When Kallus and Zeb were stranded on a frozen moon, they were actually able to cooperate, despite their initial hostility. Kallus revealed that his Bo-rifle was a gift from the Lasat warrior he defeated, in accordance with tradition, rather than a simple trophy. Injured and practically helpless, Kallus entrusted his life in Zeb's hands. When the Ghost crew finally arrived, Zeb offered Kallus to join them, with the promise of being treated fairly, though the Agent politely refused.
Kallus's friendship with Zeb forced him to rethink his beliefs about the Empire and the rebellion, eventually leading him to become a double-agent for the rebels. He was able to repay his debt to Zeb by helping Sabine, Wedge and Hobbie escape from the Skystrike Academy.
- Main article: Ezra Bridger
- “I warn you, do not underestimate that boy.”
- ―Kallus' warning to Brom Titus about Ezra.[src]
In Spark of Rebellion, Kallus arranged a trap for the Lothal Rebels onboard an Imperial freighter falsely believed to be carrying wookie prisoners. Though his attempts to capture the rebel group failed, he captured Ezra Bridger and planned to use him as bait to capture the rest of the rebels. Ezra escaped Kallus' clutches and reunited with the rebels when they came to rescue him.
Later on in Stealth Strike, Kallus warned Brom Titus not to underestimate Ezra, whom he had recently captured. He was amused by the fact that though Titus had heeded his warning, he failed to hold onto his Jedi captive and that the boy had managed to destroy the Admiral's star destroyer. Kallus acknowledges Ezra's Jedi abilities and considers him a worthy opponent.
The Grand Inquisitor
- Main article: The Grand Inquisitor
Kallus and the Grand Inquisitor worked very closely together, as they shared the same aim: to eliminate the remaining Jedi that survived Order 66. Despite this partnership, Kallus has shown to be more concerned on capturing the whole rebel Lothal cell rather than just the Jedi accompanying them. This however doesn't prevent the two from working together to bring down the rebels.
- Main article: Darth Vader
Like the Grand Inquisitor, Kallus and Vader work together to destroy the rebellion. Kallus is always in Vader's office, awaiting orders. Like The Inquisitor, Kallus does every order to try to capture or destroy the rebels, but unlike the Inquisitor and most imperials he didn't seem afraid of Vader. Kallus has shown to be very obedient to Vader's orders and displayed no reservations on the sheer cruelty of the Dark Lords plans to draw out and defeat the rebels, such as murdering Minister Tua, framing her death on the rebels and having Tarkin Town burned and its citizens imprisoned.
- Main article: Kassius Konstantine
Kassius Konstantine was a close associate to Kallus and they helped each other destroy the Rebels when Kallus was on the Imperial Star Destroyer Relentless. Also, they both shared a dislike towards the Fifth Brother. On board the Relentless, they would both make comments about the Inquisitor, which also shows the split between the Imperial and the Dark Side in the Empire.
However, despite their fairly good acquaintance, Konstantine doesn't regard Kallus as a friend, and showed no concern for him when he returned injured from a mission. Kallus was visibly hurt by this.
- Main article: Arihnda Pryce
Kallus and Governor Pryce are not on the best of terms, as Pryce treats Kallus like an underling and holds him in low regard due to his failures in dealing with the Lothal Rebels.
Grand Admiral Thrawn
- Main article: Thrawn
Kallus treats Thrawn with a degree of respect due to his rank and exceptional tactics, but is disgusted by the Chiss's ruthlessness.