Kovu is stated to be the youngest son of Zira, a follower of Scar; his two older siblings are Nuka and Vitani. He was apparently born at some point during Scar's reign, as Scar hand-picked him to be his successor. As a result, he was referred to by the Outsiders as the Chosen One. However, Scar merely adopted him, and Kovu is explicitly stated to be of no relation to Scar. His chosen path was put to a halt after Simba took back the throne from Scar and exiled the Outsiders. As a result of Scar's death, Kovu was expected to one day avenge Scar by killing Simba and ursurping the throne. As a cub, he was put through harsh training by Zira to prepare him for this task.
As a cub, he is shown to be very innocent and friendly, though he does take a moment to playfully tease Kiara when they first meet. He also had some sense of responsibility, as he took the blame for wandering off when his mother was about to tell off his brother Nuka for letting him wander off. As a young adult, he has been trained by Zira to hate Simba and the rest of Simba's pride. However, this changes as he falls in love with Kiara, where he grows reluctant to carry out Zira's plan, and becomes more friendly and caring. As a result of Zira's harsh treatment, he initially has no concept of having fun. He becomes ruthless, savage and merciless as a result of his forced training into becoming an assassin. When he reunites with Kiara, he becomes more calm, funny, prone to his true emotions of goodness, nobility and love. He proves it when he refuses to attack the king in the ambush, and when he stands up to his mother when she orders him to stand down.
Kovu is noted by many to bear a strong resemblance to Scar, especially after his face is scarred, despite not being related to him. However, he appears much more muscular and healthy looking than Scar, and is a bit darker in coloring and has dark brown mane instead of black. As a cub he resembles Simba's son Kopa.
Role in the film
One day, Kovu escaped from his brother Nuka, who was babysitting him. While wandering about, he met Kiara, Simba's daughter, who had wandered in the Outlands. The two cubs became friends after an incident with crocodiles, but they were quickly separated by their feuding parents. Back home, Zira angrily scolds Kovu for trying to befriend an enemy, but then realizes she may be able to use the friendship to allow Kovu to get close to Simba and kill him. She then praises Kovu for his brilliance, stating that he has the "same conniving mind" that Scar had.
When Kovu has grown into a young adult, Zira sends him to the Pride Lands to initiate her plan. As part of the plan, he rescues Kiara from a wildfire that has been set by the Outlanders. After rescuing Kiara, he asks Simba to allow him to join the Pride Landers. Though Simba rejects him initially, it is pointed out that by law he owes Kovu a debt for saving Kiara. As repayment, Kovu is allowed to return to the Pride Lands; however Simba still doesn't trust him. Simba chooses to reserve his final judgment until he can learn about Kovu's character, and forces Kovu to sleep outside the den away from the pride.
During his time at Pride Rock, it becomes apparent that Kovu has never had any real fun before. When Kiara chooses to chase birds along side Timon and Pumbaa for the fun of it, Kovu believes it to be training. Kiara teaches him to loosen up and enjoy himself. Over time, he begins to fall in love with Kiara, a feeling which is encouraged by a meeting with Rafiki, and begins to question his role in Zira's plot. Later, Simba finally warms up to Kovu and thanks him for saving his daughter's life the other day, and invites him in the den with the pride. The next morning, Kovu resolves to reveal Zira's plot to Kiara and that he doesn't want to be a part of it anymore because he loves her, but is prevented from doing so when Simba takes him alone to talk. After hearing Simba's retelling of Scar's story, he realizes how just how wrong his mother has been in her opinion of Scar. However, the two are ambushed by Zira and the Outsiders, who had been spying on Kovu and realized he was having second thoughts. Zira frames Kovu, claiming that the ambush was part of the plan. Kovu denies it, but Simba believes it anyway and quickly distrusts him. Kovu attempts to defend Simba, but is knocked unconscious by Vitani.
After Simba manages to escape the Outsiders, Kovu rushes back to the Outsiders to see about Nuka, who had been trapped under falling logs while trying to attack Simba. Nuka dies as a result of his wounds, and Zira angrily blames Kovu for Nuka's death, scarring him across one eye, reminiscent of Scar's appearance. In response, Kovu stands up to his mother for the first time, rejects Scar, and runs off. Back at Pride Rock, Simba believes that Kovu was behind the ambush, and exiles the rogue lion from the Pride Lands, ignoring Kiara's protests. As Kovu flees, he was being watched by Rafiki from a distance sighs very sadly realizing that Simba has completely defied his father's goals and broken the Circle of Life. However, Kovu later reunites with Kiara, who had run away from Pride Rock to find him. The two briefly discuss running away to form their own pride, but Kiara convinces Kovu that they need to return to try and unite their prides.
Kovu and Kiara return to find the Pride Landers and the Outsiders engaged in a bitter war, with Simba and Zira preparing to fight one on one. Kovu and Kiara manage to separate them, and Kovu publicly announces his intention to not let Zira harm either Kiara or Simba. As a result of his and Kiara's actions, Vitani leaves Zira's side, with the other Outsiders following her after Zira threatens to kill Vitani. When Zira attempts to attack Simba, Kovu looks on as Kiara fights her in an attempt to save her father. He sighs sadly as he sees his mother fall to her death. Simba sadly apologizes to Kovu for his mistake, and allows him to return to Pride Lands, where he is united in marriage with Kiara by Rafiki.
- (Teasing Kiara) "Bet you do, bet your daddy's little girl"
- (To Simba after Zira's ambush) "Simba, I had nothing to do with..."
- (To Kiara after rescuing her) "You're safe, in the Pride Lands."
- (Repeated lines) "What're you doing?"
- (Yelling at Zira in relation to Scar) "I want nothing more to do with him!"
- "I did nothing!"
- "You'll never hurt Kiara, or Simba...not while I'm here."
- "Kovu" means "scar" in Swahili.
- Kovu's scar resembles the Sub Zero's scar from Mortal Kombat.
- Sora's lion form in Kingdom Hearts resembles Kovu.
- Kovu was originally going to be Scar's biological son, however Micheal Eisner decided that Kovu shouldn't be related to Scar, as it would cause incest between him and Kiara as "first-cousins". His mane was also black during early development stages, another showing of him being Scar's son, and there's one frame during the scene where he meets Kiara where his hair tuff turns black.
- Obviously besides Romeo, Kovu is also similar to John Smith and Neera in that they are both on the villains' side at the start (Kovu to Zira because he is related to her, Smith to Governor Ratcliffe because he works for him and Neera because she is related to Kron) but ultimately decide to go against the villain as well as fall in love with the protagonist (Kovu: Kiara, John Smith: Pocahontas, Neera: Aladar). Unlike Kovu and Neera, however, John Smith did not end up with Pocahotnas.
- In the documentary Proud of Simba's Pride, Kovu is described as a "teenage killer". So that would mean that his young adult self is the equivalent of a 18- and 19-year old.