Voiced by David Lodge
Parasimon possessed Locomon, arriving on Earth with his brother (another Parasimon). His plan was to get Locomon to run to open up a digital zone and unleash his army on Earth. His brother possessed Rika, causing her to sing a song, and then attack Takato and Renamon before he was destroyed by Guilmon with Rock Breaker. Parasimon later tried to possess Rika himself, but Gallantmon severed his tentacles.
Eventually Parasimon's plan succeeded, and the Parasimon army invaded the world. Gallantmon, MegaGargomon, Sakuyamon, Guardromon, MarineAngemon, Beelzemon, and Justimon fought and destroyed many Parasimon, but were outnumbered. When the Takato half of Gallantmon said he couldn't let Parasimon win, he became Crimson Mode, flew into the Parasimon's digital zone, and destroyed it with Crimson Light. With the destruction of the digital zone, all the Parasimon, including their leader, were destroyed.
- Of the four main non-human antagonists, Parasimon is the only one (of the three who are killed) to not be destroyed by Terriermon.
- Of these four, he is also the only one not to get a "Not Quite Dead" moment, as Mephistomon gets after Growlmon nearly blows him up, Zhuqiaomon gets after fighting MegaGargomon, and the D-Reaper gets after fighting Sakuyamon.
- Though technically the final antagonist the tamers face, Parasimon's is on a much smaller scale to the D-Reaper, and doesn't last much longer than common Wild Ones, thus D-Reaper is still considered final antagonist.
- Parasimon speaks like a redneck. He also controls a train whose track is changed. This gives him resemblance to the trainman and the Forever Train on Star Fox 64.
- His plan to open the gateway between Earth and his world and unleash his army on Earth is similar to that of The Other and Thanos in The Avengers. Locomon opening the digital zone was like Loki using the tesseract to open the portal.
- When Gallantmon severs some of Parasimon's tentacles, as well as when some of his Parasimon minions are killed, their green blood is shown. The only other characters whose blood is shown are Mihiramon, Gallantmon (although it could easily have been his cape), and the D-Reaper.