The Foul Demon is a carnivorous demon who constantly seeks a way to enter the mortal world in order to satsify mischevious nature.
The Foul Demon entered a portal that led him to Raven's room. The Titan spotted him quickly and attempted to force him back through the portal, shooting spells at the demon until it eventually fainted. However, before Raven could complete the spell, Robin entered the room, declaring an emergency before whisking her away. The Foul Demon woke seconds later and, spotting no one around, entered Raven's room with a smile on his face. The next day, the Foul Demon hid behind a rock until a seagull landed. He crept up to the bird and swallowed it whole. Afterwords, he flew towards the Titans Tower. When Cyborg was taunting Robin about his failed driver's test, the Foul Demon soared in the background, outside the tower. While Beast Boy, Cyborg, Raven, and Starfire dined at Justice Java, he reappeared again peeking out of a nearby sewer, but quickly retreated back to its depths. After evading the other Titans, Robin was granted a passing grade to his driving exam and informed by Ed he was being used as his getaway driver the whole time. Robin revealed that he knew the whole time and wasn't warning him about the demon. On cue, Foul Demon grabbed Ed and dragged him into a portal with a grin.
Some time later, Raven decided to use Robin's staff to combat the demon as it once again attempted to return to the mortal world. Raven defeated it with a single strike.
After Cyborg brought Painbot to live in the tower, Raven's claim that the robot was evil was countered by Foul Demon's presence which she quickly trapped in its portal. During the Little Buddy Showdown, Foul Demon used its boxing abilities to attack Painbot. However, the robot activated a gigantic boxing glove and squashed the demon underneath.
The demon was very cautious, making sure to stay out of the Teen Titans' way and was an expert at concealing himself. He is a fierce opponent, but very weak as Raven defeated him in a manner of seconds. The Foul Demon was also carnivorous and was a born predator consuming a seagull and Ed with no hesitation whatsoever. He also had a talent for being in the right place at the right time, being there when the seagull landed and when Ed and Robin returned to Earth.
The Foul Demon is a black serpent-like creature with two small hands and no feet. It has two curled horns on top of his head, and small wings placed above, but not attached, to its back. He has razor sharp teeth and circular pupiless eyes which are completely white.
The Foul Demon had many abilities that helped it survive Jump City:
- Flight: The demon was capable of flying utilizing the wings on his back.
- Size Shift: The Foul Demon could transform into a colossal size to frighten its enemies.
- Whip: The demon was able to use its tail and arms like whips, seen when he grabbed Ed from far away.
- Portal: Although unclear, it is hinted the Foul Demon could summon or sniff out portals as he was inside one when he kidnapped Ed, and Raven was incapictated at the time and unable to create one.
- Boxing: The Foul Demon used several boxing moves to combat Painbot.
Teen Titans Go!
- 102a. "Driver's Ed"Template:Appear/sidenote
- 110b. "Staff Meeting"Template:Appear/sidenote
- 123a. "Little Buddies"Template:Appear/sidenote
- A number of similar demons appear with Trigon in the Cartoon Network online game, Titans Most Wanted. Each demon has five hit points apiece.