11-year-old Demonsion is a small, hunched over demon-like alien with yellow and brown skin. He has two horns and a crest on his head, with only an upper jaw and set of sharp teeth. He has small arms and legs with hooves. Demonsion has a bladed tail that resembles the shape of a scythe. The Omnitrix symbol is located on his stomach.
21-year-old Demonsion is taller and has a slim body with longer limbs and tail. His head looks very similar to his younger version. He is dressed in a black suit with green and grey stripes. He wears black gloves on his hands. The Omnitrix symbol rests on the left side of his chest.
- Portal Creation- Demonsion can slice open Portals with his blade tail to any destination within a thirteen-mile radius. These portals can even take him to other dimensions.
- Sharp Tail- Demonsion has a bladed tail in the shape of a scythe.
- Acrobatics- Demonsion can perform fantastic acrobatic feats.
- Overexertion- If Demonsion leaves his portals open for a long time, it puts a strain on his body.
- Unstable Energy- If any unstable matter or energy enter Demonsions portals, they can collapse on themselves.
- When Demonsion's homeworld, Azrifael was destroyed, his species escaped extinction by opening a portal to the Null Void, where they settled down.
- The Ink Tank changed Demonsion's design as a thank you to his creator ÆON for making a Danny Action Figure.
- Demonsion was a submission to the Create-Your-Own-Alien Contest for Chapter 8: Risen.
- Demonsion's species name Tieflinite is derived from "Tieflings" from Dungeons and Dragons.