Mtoto is a small grey elephant. He has some dark grey freckles on his face just under his eyes, and dark blue eyes. His pink inner ears have three ridges on either each, and three strands of hair stand atop his head. Under his trunk and belly is a lighter grey. He has two large but stubby white tusks sticking up on each side of his lower jaw. His tail has a dark grey tuft at the end.
Mtoto appears to enjoy following and playing games with others. He admires Beshte and wants to be just like him. He is enthusiastic and energetic, and hopes to someday become a member of the Lion Guard. He is apologetic when he makes a mistake. Though failure makes him feel quite downhearted, he allows himself to be comforted.
Mtoto is one of Bunga's loyal followers who is fanning a leaf over his head. He stops once he sees the rest of the Lion Guard approach, but Bunga urges him to continue. When the temporary dam breaks, Mtoto continues fanning his leaf in the air until he realises that Bunga has left. He follows Bunga, who enters the canyon. Realizing that Mtoto is following him with the water close behind, Bunga calls out for him to run, waiting behind as the little elephant runs into the canyon ahead of the honey badger.
Ono accidentally leads the crew to a dead end. Mtoto and the other animals look to Bunga for help, who instead tells them to listen to Kion. With no other option, Kion uses the Roar of the Elders to blast the water away and save the animals. Just a short while later, Mtoto is safe and sound with his mother, playing in the new river that Kion has created.
During the song My Own Way, Mtoto is shown walking with his herd. Fuli dashes past them and comes to an abrupt halt, facing them as she sings. Mtoto and his herd sing with her briefly before Fuli races away.
A group of Pride Landers are seen grazing peacefully when Mtoto rushes out from behind a cluster of grass, warning them of a hyena attack. The Lion Guard arrives and discovers that the "attack" was only some young animals playing Lion Guard. One explains that the game was Mtoto's idea, and Mtoto backs into the grass. Kion has Ono report that it was a false alarm, then questions the young animals about their game. They tell him that they take turns being each Lion Guard member, spare Mtoto, who is "always Beshte". Mtoto then approaches Beshte, who greets him kindly. When Mtoto remains silent, Beshte asks if Mtoto wants to ask him anything, and Mtoto proceeds to rapidly ask Beshte a series of questions. He then suggests to Gumba, Kwato, Shauku, and Kambuni that the real Lion Guard plays with them. The Guard declines, as they need to go off and train, but Beshte invites Mtoto along with them, to Mtoto's great excitement. Along the way, Mtoto explains to Beshte that he is the biggest reason that Mtoto likes the Lion Guard.
The pair of them arrive at training, where Kion announces that the Guard's first task is an obstacle course. Mtoto asks if he can run it to, knocking Ono over in the process, and Kion permits it, but orders Beshte to keep with him. Mtoto ends up failing the first two tasks, jumping over a boulder and moving through a pool of shallow water, after he trips both times and accidentally sprays Fuli with water on the second. Kion decides to try something different, and Mtoto promises to do better this time. The Guard attempts a stealth drill, and Mtoto follows Beshte for a while, but notices a sloped rock path and decides to try it on his own. When Beshte rushes to Kion with the news that he cannot find Mtoto, Mtoto announces his presence from a tall rock. However, he trips and falls, sliding down the rock, but managing to grab a small branch with his trunk. Beshte moves below him just as the branch breaks, and Mtoto apologizes to Beshte for messing up. Kion says that it may be time for Mtoto to head home. Mtoto agrees, and Beshte decides to walk with him.
As Mtoto walks home, he apologizes to Beshte again, and Beshte attempts to comfort him. Noticing that Mtoto still looks downcast, Beshte sings the song Hero Inside to make him feel better. Mtoto happily asks Beshte if he has what it takes to be a hero, and Beshte assures him that he does, even complimenting Mtoto's ability to spray water from his trunk. He adds that Mtoto may join the real Lion Guard when he is older before heading back to the others. Gumba, Kwato, Kambuni, and Shauku approach him, asking where he has been, and Mtoto proudly announces that he was training with Beshte and the Guard. He expresses a desire to play Lion Guard, and the others consent, but soon realize that the game isn't much fun without bad guys to chase. Mtoto suggests using hyraxes as the bad guys, and he and his friends dash after a trio of hyraxes, calling them by the names of the hyenas.
The hyraxes soon escape, and Mtoto asks his friends what they should chase now. Janja speaks from behind them, suggesting that he and his minions chase Mtoto and his friends. The five friends flee in terror, with Janja racing after Mtoto. Mtoto manages to evade Janja, but the three hyenas continue to pursue Mtoto, who eventually begins to tire. As he stops in front of a river, they approach him and begin debating which parts of him to eat, to Mtoto's horror. Beshte suddenly jumps out of the water behind Mtoto, scaring the hyenas away. He asks Mtoto if he can swim, and Mtoto says that his mother hasn't taught him yet, so Mtoto clambers onto Beshte's back. Beshte begins to swim further down the river, but the hyenas follow them. Mtoto at first hopes that perhaps the hyenas are simply going in the same direction, but when Cheezi and Janja pause to wait for them to pass, he contradicts himself.
Beshte instructs Mtoto to duck, and they escape Cheezi and Janja's attack safely. Beshte then defeats Chungu by launching him into the water, impressing Mtoto. Beshte soon realizes that they are heading right towards a float of crocodiles, and ducks underwater, with Mtoto lifting his trunk above. A crocodile notices and alerts the others, and they quickly surround Mtoto and Beshte, who flee, with the crocodile float swimming in pursuit. Mtoto uses his trunk to spray the nearest one with water, and Beshte compliments his shot. The rest of the Lion Guard arrives and knock the hyenas into the water, causing the crocodiles to chase them and allowing Mtoto and Beshte to reach the shore safely.
Mtoto later recounts the story of escaping the crocodiles and hyenas to his friends. Kion comments that they'd had quite an adventure today, and dips his paw into mud, using it to bestow Mtoto with the Mark of the Lion Guard. Mtoto then approaches Beshte, saying that he is his hero, to which Beshte replies that Mtoto is his.
Mtoto, Young Rhino, a hare and two porcupines are listening to a story told by Rafiki late at night. Mtoto listens inquisitively as Rafiki tells them the tale of a legendary beast known as the Zimwi. Assuring the mandrill that he is not frightened, Mtoto urges Rafiki to continue. Rafiki explains that the Zimwi only enters the Pride Lands on the night of a full moon, which Bunga points out that they just happen to have that very night. Suddenly, a strange bellowing noise frightens Mtoto, but he is relieved when it turns out to be his hero, Beshte, practising for The Bellow Fellows. Rafiki becomes annoyed at the interruption, though Mtoto begs him to continue the tale.
Rafiki does so in song form, which scares Mtoto at the end. Kion tells them to relax, certain that it's just a story. When Fuli asks Rafiki to confirm, he answers equivocally, and shoos the children away to bed. Mtoto, still frightened, turns to Kion for additional assurance. The elephant becomes spooked when the wind howls, so Kion suggests that he and his animal friends sleep together that night. They agree, and head off. Beshte starts to bellow again which once again causes Mtoto to become startled, but after the hippo apologises, he cautiously continues.
Mtoto, Young Rhino and the hare curl up next to a rock, sleeping peacefully together. A rustling in the bushes causes Young Rhino to awaken, and he promptly cries out after seeing what he believed to be the Zimwi. Once Young Rhino runs away, Mtoto and the hare notice it too, and they follow suit. The trio locate the Lion Guard who are sleeping together at Hakuna Matata Falls, and quickly wake Kion and his team up. They explain that they saw the Zimwi themselves, describing just what Rafiki had told them to the Lion Guard. Kion is visibly annoyed, and promises them that the Zimwi is just a story. Suddenly, a weird scraping noise causes them to become frightened again, though it is revealed to be Timon and Pumbaa. They then continue to explain how Timon knows of the Zimwi, though it is revealed that his Ma's cousin's friend knew an ox that was eaten by the Zimwi. Kion notices the holes in his story, but Timon does not back down on his words, telling the children that there's nothing they can do to stop the Zimwi. This worries the young animals, so Kion takes the Lion Guard out to discover what the Zimwi really is.
Mtoto rises up from the lake to sprays Young Rhino and Shauku with a spurt of water. When Mtoto asks his friends if they hear something, Shauku at first fails to hear anything, but soon sees the flock of birds flying overhead. Then, appears to worry about them and watches the Lion Guard appear from a distance, Mtoto rushes up to say hello to Beshte.
Later, Beshte and Young Rhino attend Hadithi's Royal Mud Print Ceremony. When Young Rhino leads Mtoto to the front they are told that the positions are reserved for birds only. Although this upsets Young Rhino since they are Hadithi fans too, Mtoto calmly tells them that they'll find another place to sit. This impresses Beshte, who compliments him on his kindness. Mtoto replies that he doesn't mind, since Beshte is still his number one hero. Mtoto then finds a new spot for himself and Young Rhino and together they watch the ceremony.