Rani is a strong-willed and brave lioness who takes her duty as leader seriously, prioritizing the safety of the animals in the Tree of Life. However, she can be quite short-tempered and impatient, attacking Kion and his friends after mistaking them as enemies before listening to their explanation, a lesson which she later learned. Despite her strong attitude, Rani actually hides her insecurity at the prospect of becoming the next queen, feeling that she's not ready or good enough yet to rule. This make her able to relate to Kion who was initially unsure when he was first made the leader of the Lion Guard. With Kion and Makini's help, Rani eventually able to overcome her inner doubts and embraces her role as queen.
Rani is a slender lioness, with chestnut fur with a brown stripe running down her back. The top of her ears are lined with a similar brown, and her pink inner ears have dark brown fur underneath. She has a red nose and her eyes are chocolate brown, and just above them is tawny, with the lower half becoming lighter. This brown-cream color is also present on her muzzle, her underbelly, and her paws. The back of her legs contains dark markings, similar to Kion's. The tip of her tail is dark brown.
Rani and her family mistakes the Lion Guard, who came to cure Kion's scar and Ono's eye-sight, as hostile animals, leading to confrontation between the two and Rani forbids them from ever entering the Tree of Life. She consults with her grandmother and queen of Tree of Life, Janna, about the Lion Guard. Hearing about the Roar, Janna insists that the Lion Guard is welcomed to the Tree of Life. Rani then confides to the spirit of her parents about her doubt in letting the Lion Guard to enter the Tree of Life. When the Lion Guard comes and Kion apologizes and pleads for them to cure Ono's eye-sight if they refuse to heal him, Rani is touched by Kion's concern for his friend and welcomes the Lion Guard to the Tree of Life.
While Kion and Ono are recovering, the Tree of Life is ambushed by Makucha, Chuluun, and Ora. Rani and her pride easily chase them away because the three intruders unable to work together properly. Upon hearing that Makucha and the others have followed the Lion Guard, Rani blames them for allowing intruders into the Tree of Life. Kion tries to make it up by helping the Night Pride dealing with Makucha's group, but Rani insists that her pride can deal with them alone.
Makucha, Chuluun, and Ora tries to enter the Tree of Life again through another path. She and her pride are surrounded when Ora managed to bit her brother, Baliyo, with his poison, leaving him defenseless, but Kion joins the fight. While Ora runs away after Kion joins, Makucha and Chuluun goes through the hill, but are intercepted by Kion and Rani respectively. From this fight, Rani starts to see Kion and his friends in a new light.
Rani and her pride received report that Makucha and his group is attacking an animal again. Rani arrives with her pride to save the supposedly injured Mama Binturong, who is actually working together with Makucha and the others. Rani welcomes Mama Binturong into the Tree of Life while inadvertently giving her information that Mama Binturong takes advantage of together with Makucha, Chuluun, and Ora. Fortunately, Ono able to figure out their plan, allowing the Night Pride and the Lion Guard to stop the attack.
Not long after Ono is healed, Rani, her pride, and Kion are called by the dying Janna who entrusts the role as queen of Tree of Life to Rani. As Janna passes away, Rani and the animals present mourns for her. Rani confides to Kion that she worries she can't become a good queen. Kion tells her his own experience when he was first appointed to become the leader and assures her she'll able to pull it through. When Kion reveals that he has no courage to speak with Mufasa until his scar healed, Rani encourages him to talk with Mufasa as he may help him feel better. To lift up Rani's spirit, Makini shows her paintings of the Tree of Life's past so that Rani can have and see the wisdom that Janna left behind at any time. In the afternoon, Rani is officially crowned as the new queen of Tree of Life, gaining her confidence in ruling her home.
While Rani is getting used to her role as queen, she notices Kion has lost confidence of leading the guard without the roar and suggests the rest of the Guard to convince him otherwise. When Kion decides to train his Roar on his own, Rani realizes that the Roar is returning to the Tree of Life and leaves with Bubga to speak with Kion. At the training site, she and Bunga are astonished to see the result of Kion's training. Hearing that the rest of the Lion Guard are fighting against another attack from Makucha and his group, this time bringing a back-up with them, Rani quickly returns with Kion and Bunga. She watches as Kion blows them far away from the Tree of Life for good with his new Roar.
As Kion has fully recovered, Kion and his friends are ready to return to Pride Lands, but Rani offers Kion to stay in Tree of Life together with his Guard protecting the Tree of Life as well as confessing her feelings by asking him to become her king. The Lion Guard contemplates, but are interrupted by Azaad, Jasiri, and Janja's arrival who tells them that Zira is planning to attack the Pride Lands. Understanding that the Lion Guard still has the responsibility to defend the Pride Lands, Rani bids them farewell and tells them they'll always be welcomed in Tree of Life.
After Kion decides to pass on the role of the Lion Guard to Vitani and her lionesses, Kion returns to the Tree of Life along with his family and friends. Kion accepts Rani's proposal and the two of them are officially married with Rani expresses her confidence that they'll make a good king and queen.