A list of Bular's relationships with certain characters throughout the franchise.
Family
Gunmar
As the son of Gunmar, Bular deeply loves his father and respects him. He would do anything to get his father out of the Darklands.
Bular's death affected Gunmar deeply, yet concurred about Otto's statement that his son was incredibly impulsive. Gunmar even wished to replace Bular for another champion, like Jim and Draal.
Minions
Stricklander
Strickler is Bular's former second-in-command. They are instantly shown to have a clashing relationship, as they fight over what to do with Jim (as Strickler proposes to keep him alive and unaware of their intentions while Bular wants to kill him and take his amulet to open the Killahead Bridge). Though either way, they work together for a common cause, at least until Bular's death and Strickler goes rogue against Gunmar.
However, as revealed in "Where Is My Mind?", Strickler secretly feared Bular.
Enemies
Kanjigar the Courageous
Kanjigar was both his and his father's main rival to stop their plans. Kanjigar sacrificed his own life to keep Bular's hand away from the Amulet of Daylight so it could find another successor to take his place (Jim).
Draal the Deadly
Draal despises Bular, especially after he made his father, Kanjigar, sacrifice himself to protect the Amulet of Daylight from Bular. In "The Battle of Two Bridges", the two engaged in a brief and intense battle in the museum.
After Bular is finally killed by Jim, Draal was relieved that his father has been avenged.
Jim Lake Jr.
Bular was Jim's main enemy in the first half of Part One. Bular has developed a grudging respect for Jim, but instantly wanted to kill him and take the amulet, until he realizes that he needs the boy to open the bridge. However, he went back to wanting to kill him after the bridge is destroyed again, saying that there'll always be other Trollhunters for the amulet to chose.
AAARRRGGHH!!!
As the former general of Gunmar's army, AAARRRGGHH!!! has a bit of a history with Bular. After AAARRRGGHH!!!'s defection from Gunmar and the Gumm-Gumms, AAARRRGGHH!!! provided the good trolls the information they needed to seal Gunmar into the Darklands for as long as possible. After Bular tried to kill Toby with his last moments, AAARRRGGHH!!! (out of protective rage) destroyed his petrifying body to protect his wingman.