Doctor Robotnik did not add Leon to his Badnik army until he invaded Mobius with the help of the Drakon Empire. At least one was stationed in the Rail Canyon Zone and was used as a part of a large attack on G.U.N. forces in operation there. Along with several other Badniks, Leon surprised the soldiers by sneaking up on them from behind a rocky outcrop. However, its powers of invisibility were not shown here.
Outside Sonic the Comic
Leon originated in Sonic Adventure, where it could be found in the "Windy Valley", "Lost World" and "Hot Shelter" areas. A remodeled version returned in Sonic Advance. In its Sonic the Comic Online guise, it now has a recoloured horn that matches the rest of its bodywork, which is now more green than its original blue. Its coiled tail has also been shortened.
- Newtron, a reptilian Badnik that can also turn invisible.
- E-04 Leon at Sonic News Network, the Sonic Wiki
- E-04 Leon at Sonic Retro