The relationships of Kovu from The Lion King franchise.
At some point in his reign, Scar adopted Kovu as his successor and protege and raised him like his own. Despite this, Kovu never showed any particular familial affection for Scar or even once considered him as his father. Due to Zira's brainwash, once he reached adolescence, Kovu initially is loyal to Scar's memory and determined to avenge him. However, after falling in love with Simba's daughter (and Scar’s grandniece) Kiara, Kovu began to doubt Scar and became afraid that he may have the same darkness as Scar did as he felt Scar is a part of him. After fully learning Scar's true nature, he completely rejects Scar's legacy and sides with Kiara.
Despite the harsh conditions of their environment, and the pressure of Kovu's status as Scar's chosen heir, Kovu appeared to have a decent mother-son relationship with Zira during his cubhood. He appeared to harbour affection toward her and strived to please her. At the same time, Kovu also feared his mother and didn't dare to anger her. Out of her three cubs, Zira gave her attention to Kovu the most because Scar chose him to become his successor. As a result, Zira always made sure that he's being watched when she's not present. While she favours Kovu, it still doesn't stop her from being harsh on him even when he was still a cub and brainwashed him into hating Simba. All expectations Zira has for Kovu, however, vanished after Kovu rejected Scar's legacy and betrayed her, leaving Zira with nothing but bitterness and disappointment at her youngest son. Despite this estrangement, Kovu still loved his mother and when she fell to her death, he mourned for her.
Kovu appeared to have a close sibling relationship with his older sister Vitani, being on much better terms than he was with Nuka. They appeared to be close in age, and presumably often played together as cubs. Unlike Nuka, Vitani doesn't harbour any jealousy towards Kovu being the chosen one, and in fact, fully supported him in becoming king. However, due to her loyalty towards their mother, Vitani didn't hesitate to attack Kovu when he betrayed them and at first, also blamed him for Nuka's death. After she was moved by and realized the truth in Kiara's words, Vitani defected to Simba's pride and reconciled with Kovu.
Much like Scar's resentment toward Mufasa, Nuka harboured an intense and hateful sibling rivalry toward his younger brother for his position as Scar's chosen heir and the apparent favouritism that Zira gave him. Nuka constantly refers to Kovu as little termite out of spite. Although, if he's in trouble, he doesn't hesitate to ask for Kovu's help, as shown when Kion pinned him and Nuka asked for Kovu's assistance. Kovu, for his part, held love for his brother, as he defended him against Zira's accusations and was devastated by his death.
Kovu first met Kiara as a cub. After both worked together to escape from crocodiles, they became fast friends. However, this didn't last long as they're separated by their feuding parents. Years later, Kovu, who has been brainwashed into hating Simba, merely saved and got close to Kiara so he could kill Simba. As the days pass, Kovu and Kiara begin to spend more times together. From Kiara, Kovu learned how it feels to have fun and just enjoy himself. Kovu gradually falls in love with Kiara and decided to abandon his mission to kill Simba. When Kovu was exiled after Simba falsely accused him of setting up the ambush by Zira, Kiara is heartbroken and immediately leaves to find Kovu. When the two of them are reunited again, Kovu suggests they elope and form their own pride, but Kiara convinced him to try reuniting their prides. After they stopped the war and reunited the two prides, Kovu and Kiara are happily married.
Friends and Allies
Simba, on his part, mistrusted Kovu due to his Outsider heritage and status as the adoptive son and chosen heir of Scar. After reuniting with Kovu, Simba is deeply suspicious of Kovu's intention in saving his daughter and initially refused to allow him to join the pride, only reluctantly allowing him because Nala and Zazu reminded him of the law set by his father.
Simba eventually started to trust and warm up to Kovu, unfortunately, this trust was completely destroyed when Simba was ambushed by Zira and her pride, and Zira claims that Kovu led him into the ambush (which was a lie). As the result, Simba once again only saw Kovu as Scar's heir and exiled him without even trying to listen to Kovu's explanation first.
After intervening alongside Kiara to stop the fight between the Outsiders and Pridelanders, and showing that he won't let Zira hurt her or Simba, Simba comes to realize that he was wrong about Kovu and accepts him back into the pride. He then allows Kovu to marry Kiara and begins grooming Kovu as his successor to rule alongside Kiara.
Kovu and Kion met in the Outlands sometime after he met Kiara. They did not interact much together but Kovu had no hostility toward Kion during the events that followed after their meeting. When he learned Kion is Simba's son and is willing to talk to his father to allow the Outsiders back to the Pride Lands, Kovu is delighted as he could see Kiara again. When Zira revealed to have led Kion into a trap, Kovu questioned his mother's intention and quietly disagreed with her, preferring that they becoming friends. Kion at first didn't think well of Kovu after his experience with Zira and assumed he meant to harm his family when they were reunited years later. However, after learning how the Outsiders have joined Pride Landers, Kion is quick to accept Kovu as his brother-in-law and both are on better terms since then.
At first Timon and Pumbaa disliked Kovu since he was the son of Zira. They were both on Simba's side since they're his best friends. During Kovu's stay in the Pride Lands he got to know Timon and Pumbaa. He had fun playing with them while he was training with Kiara. They seem to become good friends.