Devon and Cornwall are both loyal and comical, but they continuously argue back and forth, and not just making sarcastic comments to one another, which lacks the ability of flight and fire, but they do soon learn to put aside their differences and work together to save Camelot.
Devon is highly intellectual and posh with an English accent and does not appreciate his brother's nagging towards him and often gives snarky comments about him. He is very polite and honorable in all ways.
Cornwall is crude, gruff, but loyal with an American accent and doesn't take a liking to his brother's politeness and sometimes his slow-wittedness. Cornwall can often make fun of Garrett behind his back, and flirts with Kayley sometimes. Cornwall can name call Devon briefly at times.
Devon and Cornwall are obese conjoined, purple dragon, they have small wings, Turquoise belly, face and inner wings.
For Devon, He has an slender head, tall neck, red long horns, and an thin right arm. As for Cornwall, He has an short neck, obese head, short red horns, and an thick left arm.
Role in the film
Devon and Cornwall are first seen as Kayley and Garrett were hiding in one of the eggshells. After being frightened, Cornwall calls out to the heroes into thinking that they are ferocious dragons and made puppet shadows on the wall. After Garrett finds out that Devon and Cornwall were only slim and fat dragons but conjoined as one. Devon and Cornwall, Kayley and Garrett (including Ayden) were chased away by the real ferocious black dragons. With Devon and Cornwall's help, they managed to escape the attack and Ruber by hiding in an underground cave. Devon and Cornwall then bicker over each other of how they wanted to be separated in their own ways by singing their song. After they finished singing, Kayley, Garrett, Ayden, along with Devon and Cornwall manage to escape Dragon Country. When Devon and Cornwall explain that when they go back in Dragon Country, They'll be banished for breaking a dragon's cardinal rule: Never help a human. Garrett allows Devon and Cornwall to join the group, but tells them "no more singing".
At night, Devon and Cornwall can smell the dragon meat that Ruber and his men had cooked earlier and could whip for something. They are trying to light a fire by rubbing a stick on many stick but fails as many sticks come alive and ran away. Devon and Cornwall fail to capture a stick that is running away and when Ayden laughs at them, Cornwall swallows him but Devon on the other end, spits him out unharmed. Devon and Cornwall later arrive back at Kayley and Garrett.
The next morning, They find the belt of Excalibur but when Kayley questions Garrett causes him to miss a signal from Ayden and he is injured by Ruber. Devon and Cornwall run in fear as the trees emerge from the ground. Kayley uses one of the moving trees to trap Ruber and his men and takes Garrett somewhere safe.
Kayley manages to find a cave to place Garrett against a rock, she takes some healing leaves and place it on Garrett's wound as Devon and Cornwall look on sadly. As Garrett heals, Kayley and Garrett develop a romantic bond against one another with Devon crying in joy as Cornwall took a green leave as an umbrella. Devon and Cornwall gets tangled up with the tongue plants who kiss them, Devon and Cornwall manage to keep up with the pair to find Excalibur.
When reaching the Rock Ogre's cave, Devon and Cornwall find a skull that is Uncle Yorik. They manage to find the ogre holding Excalibur. They form a human chain with Devon and Cornwall holding on with their tail on a rock. After they manage to get Excalibur, they manage to escape. After reaching the end of the forest, Garrett decides to stay in the forest with Ayden because he felt that he doesn't belong in Camelot. When Devon and Cornwall argue until they are cut short when they see Kayley captured by Ruber who has now gotten hold of Excalibur. Devon and Cornwall hide behind a rock to see Ruber melding Excalibur to his arm, they run off back into the forest to warn Garrett of this.
After Devon and Cornwall explained what happened, Garrett rushes to rescue her. Devon and Cornwall now begin to agree on hating Ruber, thus gaining their ability of flight. When Ayden tells Garrett this, Devon and Cornwall then again to disagree causing the two to fall in a mud puddle. Garrett tells Devon and Cornwall that the reason their abilities cannot work, because they never agree on anything.
Devon and Cornwall eventually make up and become friends. Garrett, Ayden, Devon and Cornwall manage to rescue Kayley from Ruber's men by knocking them into the moat. Devon and Cornwall then rescue Ayden from the Griffin by breathing fire at him. Later, When Ruber is being disintegrated, Devon and Cornwall manage to separate from the wave of magic from the stone, But the pair decided to reunite and become as one. They are later seen with Ayden as Arthur pulls out Excalibur from the stone. Devon and Cornwall are last seen attending Kayley and Garrett's Knighting Ceremony.
At the time Quest for Camelot was released, Devon and Cornwall appeared in specially-made promos and bumpers for a specially-themed broadcast of Kids' WB!, called "Devon and Cornwall's Dubba Dragon Day".
Devon and Cornwall do not get along with each other, despite being conjoined twins, and thus lacking their ability of flight and breathing fire. Later, when Garrett points out to Devon and Cornwall, that they won't fly or breathe fire, because they disagree on anything, Devon and Cornwall learn their lessons, put aside their differences and rivalry, and became friends. They save Kayley from the ironmen, and Ayden from the Griffin. Although that are finally spilt in their separate forms, they decide to be better off as one.
- (Devon explaining to Garrett why they are conjoined twins) "Well, frankly We're the reasons cousins shouldn't marry."
- (Devon and Cornwall first meet Kayley)
- Devon: Enchantee mademoiselle, I'm Devon and this (referring to Cornwall) growth on my neck is Cornwall.
- Cornwall: (whilst flirting with her) But you can call me Corny for short.
- Devon: Yes. Short on wit, manners, and charm. Everything I hold dear (Cornwall grabs his snout)
- Cornwall: How bout holding ya breath?
- (both, singing) "All what I could be if there was only me? Oh, Would I do, If I didn't have you!"
- (Devon comments Cornwall's attempt to light the fire) "You know, there's nothing more pathetic, than a flame retardant dragon."
- (Devon looks at the carcasses in the ogre's cave, and answers sarcastically and quietly) "Ooh, charming place. I must get the name of his decorator."
- (after Garrett had departed back into the forest, feeling no longer part of Camelot)
- Cornwall: (to Kayley) Forget about him. You're better off alone. He walks funny, He even looks funny. People throw darts at him.
- Devon: (disgusted) How can you be so cold-blooded?
- Cornwall: I'm a reptile. (he sticks his tongue, like a lizard would)
- Devon: Listen to me, you Jurassic twit. Kayley deserves someone who love her. Someone, who'd hold her in his arms (he hugs Cornwall), rubs his fingers into her hair, (he plucks out one of Cornwall's hair, and then gets into Cornwall's face) Look deeply in her eyes, and make her feel like a real woman! (he kisses Cornwall, who splutters in disgust. Devon then turns green and they begin to splutter)
- Cornwall: I can't believe you've got your tongue on my gums!
- (they agree on hating Ruber, thus enabling their ability of flight, which Garrett points out.)
- Devon: Gosh. He's right, We're are flying!
- Cornwall: I did it! Yes I love me, yes (his kisses his bicep)
- Devon: (smacking his fist on Cornwall's head) Excuse me, eco-maniac. Don't you mean I-
- Cornwall: No, no! (Then, they fall into the mud puddle.)
- Cornwall: (to Devon, who is making kissing noises) Hey, Don't even think about it.
- Respectively, Devon has a English accent, while Cornwall has an American accent.
- Devon's line "You'll be nothing without me, You'd be extinct, you'd cease to be" is an reference to the parrot sketch from Monty Python's Flying Circus where Eric Idle (the voice actor for Devon) starred in.
- Devon and Cornwall can reference various films, stages, and television shows through the film.
- Cornwall's voice actor Don Rickles also voiced Mr. Potato Head from Disney-Pixar's Toy Story Series.
- Coincidentally, Cornwall named himself "The Dragon King" in the duo's song, referencing The Lion King that is made by Disney.