|“||I... am the world, and the world... is Ommadon.||„|
|~ Ommadon to Peter|
Ommadon is an evil red wizard whose brother, Carolinus, then proceeds to explain to the other three of the magic brothers that the world of magic is dying. To save it, they must join together to create the "Last Realm of Magic," a protected place where magic will live on after humans stop believing in it. Ommadon refuses to aid his brothers, and vows to dominate humanity by infesting humans with greed, in an attempt to stop magic's death by force. This rather violent and sadistic solution outraged the other wizards, but the only way to stop him is to take his Red Crown, the source of his dark magic.
In the 20th century, Peter Dickenson, a poor, dreaming scientist and inventor, is also a descended from an ancient hero, and is asked to begin a quest for this purpose and is transported into the failing world of magic. He meets three wizards, two dragons, and the beautiful Princess Melisande, who is a Wizard's foster-daughter. Despite his joyful surprise by the fantasy world (particularly the Dragons), Peter has doubts about being a hero and his mission, so Melisande has to talk with Peter and tries to comfort him. Unfortunately, Ommadon witness their conversation and sends Bryagh to kidnap Peter, but a magical mishap (in an attempt to save him) leaves Peter in the body of the house-dragon Gorbash. Knowing nothing about being a dragon or about magic, Peter travels with two other companions, a knight called Sir Orrin Neville-Smythe and the dragon Smrgol.
During the journey, it is Smrgol who teaches Peter the details of being a dragon, something that accuses his scientific curiosity about the dragons physiology, much to Smrgol chagrin due to the latter's insistence in rationalize his teachings (even though his theories have a basis in logic and accuracy deduction). At their campsite, Ommadon sends rodent-like creatures called sandmirks to attack the party with their insanity-inducing cries. The blue wizard Solarius offers the dead wolf Aragh his life back in return for the death of the sandmirk queen. He agrees to join the quest. Princess Melisande is put into a deep sleep by the cries while using her magical abilities to see the party. The group presses on, and they are attacked by Giles of the Treetops and his elves because they are mistakenly suspicious of the dragons. The archer Danielle of the Woodlands saves the group because she recognizes Sir Orrin. Learning the truth, Giles and Danielle join the travelers.
The survivors move on to Ommadon's Red Realm and defeat the gigantic Worm of Sligoff. They use magic gifts, a shield and a flute, to defeat Ommadon's spell of despair and to put a flight of dragons to sleep (including Peter occupying the body of Gorbash). The magic flute does not defeat Ommadon's dragon Bryagh, who kills Danielle, Aragh, and Giles. Sir Orrin slays Bryagh with his sword while being burned alive by dragon fire. Ommadon magically appears claiming victory. Peter reappears to confront Ommadon when he realizes that two things cannot exist in the same place at the same time. Ommadon then transforms into a monstrous body with six dragon heads to attack Peter. Peter then uses his scientific knowledge to deny all magic; in a dramatic conclusion, Peter alphabetically lists as many branches of science as possible, and Ommadon, whose teachings and power are based on superstition and the ignorance of others, tries to match Peter's list with his own list of foul creatures (harpies, witches, trolls, demons, etc.) but cannot withstand Peter's onslaught of science, and literally dies of disbelief.
The death of Ommadon allows the party to return to life. Carolinus arrives, along with the remaining two magic brothers, and succeeds in creating the 'Last Realm of Magic' but sadly concludes that Peter is gone from the magic's reach. Princess Melisande wakens from her slumber and informs them Peter appeared and woke her with a kiss. Carolinus concludes that Peter's actions suggest he may still believe in some magic after all. She asks to join him in 20th century Boston, and Carolinus reluctantly agrees.
- Ommadon was voiced by James Earl Jones.