Makuu is a large crocodile with bright green scales and a light green underbelly. He has several dark green scales running along his back and on his tail. He has some light green spots running along his back, and small black claws. Makuu has a long snout, and his eyes are yellow. Physically, he is also very strong.
Makuu is young and courageous, but is very prideful and arrogant. He is very boastful about his successes. Makuu is tough and strong, but he is somewhat blasphemous and disrespectful towards others and always eager to pick a fight, believing that physical strength is the most important part of being a leader. He has been described as a show-off. Though physically strong, Basi notes that his fighting technique is inferior to that of Pua's. He believes that only weak and cowardly leaders are afraid to fight.
Makuu does, however, know when he cannot win a fight, and will back down if so. However, he is a bit of a coward using Nala as shield to protect himself from Kion's roar.
He can also be somewhat sacrilegious and impolite of the rules especially when it comes to the Flood Plains. He does happen to have a bit of disrespect for the hippos since they follow the rules of the Pride Lands.
Makuu is seen sleeping peacefully in the water near some hippos. However, Bunga leaps over his head whilst playing Baobab Ball, waking him up promptly after he lands on his nose. As Kion approaches shortly after his friend leaps away, Makuu turns and growls, startling the young cub.
Pua approaches Basi and asks if the fish in Big Springs are ready, but he asks him to swing by next week since there aren't enough for the whole float. Makuu disagrees with Pua for agreeing with Basi to return later when they were promised fish at Big Springs that day. He believes that Pua is weak, and challenges him to a Mashindano, which Pua accepts. At sunset, the two go into battle. Even though Makuu's techniques are poor, his strength and youth secure him his victory. Makuu becomes the new leader, and watches with great delight as Pua is banished from the Crocodile Float, taunting him as he leaves.
After becoming leader, Makuu takes over Big Springs, which causes the rest of the animals to scatter throughout the Pride Lands. Kion and the Guard try to reason with Makuu but he refuses to listen and demands a fight. When Kion refuses to fight, Makuu assumes that Kion is afraid, which Kion denies.
But with Mufasa's words of wisdom, the Lion Guard return to the crocodile leader telling him that if he wants a fight, then the Lion Guard will bring it. After Makuu sees Kion demonstrating the Roar of the Elders in the Grove of Trees, he and the rest of the crocodiles leave Big Springs. Before they clear out, Basi tells Makuu that he is welcome back once the fish have repopulated.
Makuu overhears Kion tell Bunga that he has plans to quit using the Roar forever. When they leave, Makuu has an idea. When another member of his float asks if they're going back to Big Springs, Makuu informs him that they're going for something else.
Soon after, Makuu and his float take over The Flood Plains, driving all the other animals out by force, including a mongoose and Thurston. The mongoose bumps into Fuli and relays the information to her, and soon she, Bunga and Beshte arrive at the scene. They order Makuu to leave and, when he refuses, Fuli tackles him whilst Bunga and Beshte deal with two other crocodiles. Fuli is nimble enough to avoid most of Makuu's attacks, but soon falls prey to his technique. When she falls into the water and scurries onto Beshte's back, he reveals that the rest of his float are present, surrounding the trio.
Kion and his mother Nala approach Makuu soon after, having heard from Ono of the problem. They explain that Makuu is free to share The Flood Plains, but he is not entitled to all of it. He responds by forcing Nala into the water, and getting his float to surround her. With the belief that Kion won't use his Roar to avoid hurting his mother, he taunts the lion cub. Kion then tries something new, which saves his mother from the crocs. He assertively demands Makuu leave, and uses the Roar of the Elders to throw Makuu out of The Flood Plains.
Makuu and one of his float members locate Young Rhino, who is trapped among the reeds of the Flood Plains. He is sure no one will find him in the mess, but Beshte arrives just in time. Makuu thinks he has the upperhand with a two on one fight, but Basi arrives and then Makuu swims away saying that the hippos always follow the rules.
Later during the day, another rainstorm breaks out and Makuu plus four of his float members locate a wounded Basi in the Flood Plains. He believes that taking out the hippo will mean no more rules to follow, and he starts to approach him when suddenly Beshte returns to defend his father. Makuu reminds them that they're outnumbered and that they're crocodiles, showing no fear. However, Beshte and Basi create a new Hippo Lane behind them. Makuu is adamant that they won't get away so easily and he orders his float members to follow them. They chase after the hippos which leads the float to Bupu's Herd as they stampede down the lane. He commands them to dive but despite diving, the crocodiles are trampled by their hooves. When the injured crocodiles surface, Beshte orders them to leave and they do so, in too much pain to try another attack.
After Mwenzi the tickbird falls out with his best friend, Kifaru the rhinoceros, he perches near a lake. Ono approaches him, and warns him that Makuu and his float frequent the area, but Mwenzi refuses to leave, untrusting of the egret. As the two speak, Makuu notices the pair nearby, but remains silent. Once Mwenzi has warmed up to Ono and the pair decide to leave, Makuu strikes the branch and Mwenzi, sending the tickbird soaring. Ono is able to save him from Makuu's jaws and places him on a high branch, but Mwenzi's wing has become injured. When Ono flies away to get help, Makuu laughs below.
Makuu starts to smash his tail against the tree continually, hoping to knock the tickbird from his perch. Mwenzi is confident that he cannot be reached, but Makuu is adamant that he has a trick up his sleeve. He dives underwater and pounces up, snapping away a large portion of Mwenzi's branch. With the tickbird panting rapidly, Makuu assures him that he won't be so lucky next time. But before he has a chance to try a second time, Kifaru arrives to save his friend. But without his tickbird, the rhino races straight past Makuu and into a tree.
Seeing a great opportunity, Makuu calls for the rest of his float. They approach the rhino, but are distracted by the Lion Guard's arrival. Annoyed by their presence, Makuu warns Kion to stay out of their business. When he refuses, Makuu pins the lion cub to the ground. With Makuu and the other crocodiles distracted, Mwenzi leaps down and starts to instruct Kifaru on how to get loose. Once free, the rhino knocks away the other crocodiles. With the danger rising, Makuu decides to give up, claiming the meal not to be worth it. But Kifaru, still furious, charges and knocks Makuu away himself. The crocodiles then retreat.
When a storm causes a flood in the Pride Lands, Makuu's Float take advantage of the water around them, going so far as to trap Zuri on a rock. Kion approaches Makuu and asks him and his float to leave, but Makuu reminds Kion that his territory is anywhere where there is water. He leaves Kion with a difficult decision on how to proceed.
When Reirei starts to float down into the swamp, Makuu and his float await her. Depending on the path chosen, either Beshte or Ono guide her away from the crocodiles to safety.
Makuu was misnamed Mapu on an official Disney site, even mistaking him as an alligator, despite alligators not being native to Africa. Although his name was corrected on the site, his species was not.
It should be noted, however, Makuu's teeth are more similar to an alligator's in that the only upper teeth sticks out when he closes his mouth. Being a crocodile, his lower teeth should also be sticking out.