MadLeomon is a powerful yet very overconfident warrior that serves under the command of Lilithmon & Tactimon. He usually fights alongside Mervamon or SkullSatamon.
MadLeomon leads his Empress' very first invasion against the Earth. However, he is soon faced by the DigiDestined & is beaten by their Digimon, DinoOmnimon, after an intense fight. He also becomes notable for telling Lilithmon what to do frequently, & always promises that they will get revenge for their schemes' failures, even though they really don't in the end. He's also called a "bumbling fool" by Lilithmon, & is scolded by Lilithmon vehemently, being called a "worthless misfit" & a "dweeb". This pattern also happens when Tactimon is introduced as well; in addition to insulting the now apparently-incompetent feline warrior, he often blames MadLeomon for his own failures, & has a habit of silencing him (& Grumblemon & Etemon) frequently.
Ever since then, MadLeomon fights the DigiDestined & their Digimon, growing a strong hatred for Taylor & Alex for their continual victories in single combat. MadLeomon also has a Digimon of his own known as Craniamon, an ancient war Digimon, but this Digimon is defeated by the DigiDestined's "CoreOmnimon & UltimateBrachiomon" after a prolonged battle. He is also involved in one of Brick & Stick's more memorable encounters with a Digimon, in which MadLeomon (giant sized) picks up a bus with the two bullies inside.
When Tactimon arrives on the moon, MadLeomon eagerly abandons Lilithmon for his old master, regaining his wings in the process. As Tactimon's right hand man, MadLeomon leads many missions for him, encountering Alex (now with Baihumon) again & again. Each time they fight, Alex will best him, sending MadLeomon back to Tactimon in disgrace. When Lilithmon returns to the moon & marries Tactimon, MadLeomon is aghast. When he finally discovers that it was a sham, he immediately sets out to make things right & has Wisemon create an antidote for the love spell Lilithmon used. Unfortunately for Madleomon, it is revealed that Tactimon had come to love Lilithmon on his own, potion or not. Even after Lilithmon drops her secret plans of usurping Tactimon, MadLeomon still hasa massive dislike for her. Often paired with SkullSatamon, MadLeomon is disgusted by the skeleton Digimon's stupidity (& stench), although they eventually become friends of sorts.
MadLeomon is also essential in Tactimon's powering of the Shogun Digimon, as he soundly defeats Shurimon, allowing Tactimon to capture Shurimon to use him as a power source for the Shogun Digimon.
MadLeomon & SkullSatamon plant a bomb outside of the Command Center, but it is defused by Kokuwamon. The two are then given a map of the Command Center's Basement (that Tactimon finds) & attempts to blow it up. The bomb goes off, & the Command Center explodes. During the chaos, MadLeomon steals the Zeo Crystal with the help of SkullSatamon. During this, MadLeomon finally beats the DigiDestined by helping destroy their Ninja DigiMemories.
When Oozemon overthrows Lilithmon & Tactimon; MadLeomon & Oinkmon switch sides almost automatically after Oozemon traps both Lilithmon & Tactimon in a snowglobe, depriving them of the their powers.
MadLeomon stands by Oozemon's side as he enacts his plans. But once he sees the DigiDestined return with their new powers, he decides it's time to fly off.
At the very end, Lilithmon & Tactimon are not pleased with him as he takes over their palace after Oozemon is killed, calling himself King MadLeomon.
However, they somehow lose the Crystal, & their memories (& in MadLeomon's case, his wings), & ends up wandering around Tokyo. They eventually find Brick & Stick, & end up becoming their butlers in exchange for food & shelter. Tactimon & Lilithmon eventually find them & restore their memories (& MadLeomon's wings). They return to their employers & help them in their quest to destroy the Machine Empire.
MadLeomon Winged Mode
MadLeomon Winged Mode is MadLeomon's former version with wings.