|Voice actor(s):||(Ja:) Hiroaki Hirata|
(En:) Paul St. Peter
Devimon had infected Leomon with Touch of Evil attack, having Leomon attack the DigiDestined against his will. He was briefly freed from Devimon's control by Tai's Digivice to save Tai and Agumon by fighting Devimon. However, he was infected with another Touch of Evil attack and was under Devimon's control once more. He later appeared to attack Mimi and Izzy when they were in Centarumon's temple, but they drove him off with their Digivices. When ordered to kill TK and Patamon, he was infused with an additional eight black gears which increased his size and power and darkened his colour tone, subsequently being able to incapacitate the obstructive Garurumon and Greymon with his Fist of the Beast King attack. He was freed by Matt and Tai with their Digivices. When he was freed by the children, he aided them in the final battle with Devimon, but was defeated. When Ogremon decided to get revenge for Devimon's death, Leomon scared him away. He also aided in the building of a raft that the kids needed to get to the Server continent.
While the DigiDestined tried to save their world from Myotismon, the Dark Masters took over the Digital World. Leomon was among those who tried to fight back. After being exposed to the power of the DigiDestined's Digivices a few times when he was under the control of Devimon, he had inherited the ability to warp digivolve to his Mega form of SaberLeomon (skipping the ultimate stage). He rescued Mimi, Palmon, Joe, Gomamon and Ogremon from being found by MetalEtemon and took them to where Digitamamon's diner was. When MetalEtemon attacked, Leomon digivolved to SaberLeomon to fight him. He threw himself in front of an attack heading toward Mimi, being mortally injured in the process. Gomamon digivolved immediately to Zudomon and attacked with his hammer sparks but could not hurt MetalEtemon since his body was coated with Chrome Digizoid. However, when Zudomon then threw his hammer at him, it cracked his body because the hammer was also made of Chrome Digizoid. With his remaining strength, SaberLeomon punched his claw into the cracked wound, destroying MetalEtemon, but causing himself to revert to Leomon. As he died, Leomon made his peace with his arch-nemesis, Ogremon, and now waits to be reborn at Primary Village.
Digimon Adventure tri.
Later, Ogremon realises in the Real World, leading Maki Himekawa, Daigo Nishijima and the army to try and kill him with machine guns and bazookas. Ogremon however, barely takes any damage and destroys the car Maki and Daigo came in. When he was about to kill the two of them, Leomon appears and takes Ogremon away through a distortion. Ogremon is later found by Mimi and Meiko Mochizuki, who are sent by Izzy to fight an Infected Digimon who had just realised in the Real World. Meicoomon and Togemon fight Ogremon, however due to the infection powering him up, Ogremon easily defeats the duo. Before he can kill them though, Leomon appears once again and drags Ogremon through yet another distortion.
Leomon is then brought to Koushiro "Izzy" Izumi's office by Taichi "Tai" Kamiya, where Leomon explains that Ogremon, and other Digimon, started to act crazy, stating it was a mutation - though Izzy corrects him and states they're referring to them as Infected Digimon. Leomon informs them that the infected Digimon appeared first, with the distortions between the Digital World and the Real World coming afterwards. The DigiDestined leave their Digimon in Leomon's care whilst they go to the School Festival, but the partner Digimon attempt to convince him to take them. It's not until Meicoomon puts on a cute act that Leomon takes them, as the act caused him to fall in love with her. Putting on a disguise, and hiding them all under his coat - he attempts to keep them there for only a short time in secret, however all nine of them break free and run around the festival. Meicoomon is then tricked by Maki into leaving the rest of the group, then leaves Meicoomon on her own to get ice cream for the two of them, which was a ruse so that the Digimon Emperor could kidnap her. Leomon attempts to rescue her, however Leomon falls to his knees, showing that he too had become infected. The Digimon Emperor then takes Meicoomon into a distortion, so Gomamon, Palmon and Leomon - once he regained control of himself - follow the Emperor, though he summons Imperialdramon Dragon Mode, also infected, to attack the trio.
During the fight, Leomon once again succumbs to the infection, leaving Palmon and Gomamon to fight alone. When Mimi and Joe overcome their personal problems, Palmon and Gomamon are able to Digivolve to Rosemon and Vikemon, whilst Imperialdramon Mode Changes into Imperialdramon Figther Mode. The fight leads to Imperialdramon about to finish off the two of them with a Giga Crusher, however Leomon is able to regain control of himself, attacking Imperialdramon and causing the Giga Crusher to fire aimlessly into the air. Leomon then instructs the two of them to finish off Imperialdramon, leading Rosemon to attack with Forbidden Temptation and Vikemon Arctic Blizzard to kill Impieraldramon Fighter Mode. Leomon then demands for the Emperor to let Meicoomon go, which he does. After leaving the distortion, Leomon hugs Meicoomon telling her she's safe now - however Leomon once again shows signs of the infection, which terrifies Meicoomon and causes her to slide evolve into Meicoomon (Saltation). She then proceeds to murder Leomon, and then flees through a new distortion that Meicoomon herself opens. Everyone is shocked at what they just saw, expect Maki - who smiles and enjoys Leomon's death. Due to being killed in the real world, Leomon's death, unlike last time, is permanent. Although the Reboot allows permanently deceased Digimon to be reborn.
SaberLeomon is Leomon's Mega Form. After being exposed to the light of the Digivices, Leomon gained the ability to evolve straight to his Mega form, SaberLeomon. He remained an ally, but admitted he couldn't quite control the ability to evolve. He was killed by MetalEtemon when he used up all his strength to jab his claws into MetalEtemon's wound. However, Ogremon said that the Village of Beginnings had been ruined by the Dark Masters, so Leomon could not be reconfigured, along with Chuumon, Whamon or Piximon.