Monarch is Xaxon's Lepidopterran (a species from the planet Lepidopterra) form, just as Stinkfly is Ben's Lepidopterran form. He appears as an insectoid creature with green skin. He has, rather than eyes directly on his head, four large green eyestalks with orange eyes. These eyestalks are connected at the roots (the two on each side are connected, that is). His legs are four spike-like appendages. The back legs are normal, but the front two are shaped more like scythes. He has raised white, v-shaped circles around his entire torso and ending at his white, vaguely home-plate-shaped tail. The rest of his torso is black. He has long green arms with three black claws on each hand. He can walk, but usually flies with his oddly-shaped wings. His black head is shaped like a regular human head with a craggly chin and no eyes or nose. His Protomnitrix Symbol is on his chest.
As a Lepidopterran, Monarch can fly, shoot adhesive, stinky mucous, flammable, stinky mucous, and other kinds of...mucous from his eyes and mouth, use his legs, hands, and tail for melee attacks, use strength which would seem impossible for a form such as his, and see all around himsef with his eyestalks. Since Xaxon spent much time with another Lepidopterran, Monarch has incredible maneuvering abilities.
- Monarch appears very similar to the Lepidopterran Prisoner from Ben 10: Secret of the Omnitrix.
- Stinkfly, from Ben 10 Planet - the Ben 10 Resource!