Edgar is a skilled scientist and inventor, born and raised in Nod's Limbs along with his older twin sister Ellen. When he was seven years old, his parents departed on an "around-the-world holiday" and never returned. Since then, Edgar and Ellen spend most of their time pulling elaborate pranks both on each other and the residents of Nod's Limbs.
He plans many of the twins' schemes and diagrams. He is also an accomplished escape artist who idolizes Harry Houdini. Wherever Edgar goes, so does his satchel of gadget oddities, good for chaos in any situation.
In most situations, Edgar starts out calm and confident, but when things start to go wrong he has a tendency to panic. Edgar can be quite absent minded about some details, which often leads to disaster.
During the course of the series, Edgar and Ellen discover dozens of secrets about their seemingly perfect town, develop relationships with their mysterious groundskeeper, Ronan Heimertz, and their strange, one-eyed pet, Pet, and become the heirs of Augustus Nod.
Edgar was born to an unnamed couple two minutes and thirteen seconds after his sister Ellen in Nod's Limbs. Little is known about his life with his parents except that he and Ellen made their mother suffer for hours during labor due to them fighting over who was born first. Seven years later their parents abandoned the town for "an around the world holiday", according to the note they left behind and never returned. Edgar and Ellen have been more or less on their own ever since, except for their pet, Pet, and their mysterious groundskeeper, Ronan Heimertz. Edgar and Ellen often pulled pranks on people (and each other) to cure their boredom.
Edgar and Ellen once decided to steal the pets of the youngest citizens of Nod's Limbs and transform them into exotic animals worth millions to finance future pranks but their plan backfired and the twins got beaten up and bathed in mud by the pet's owners. ("Rare Beasts")
When Mayor Knightleigh planned to destroy the Gadget Graveyard in order to build the Knightlorian Hotel, Edgar and Ellen managed to steal Stephanie Knightleigh's position as tour guide, taking the celebrities for a ghastly tour. The twins manage to sabotage the world's largest French toast festival, seemingly crushing Knightleigh's plans, until one tourist writes a positive review on Nod's Limbs tourism. ("Tourist Trap")
Edgar and Ellen found out that Mayor Knightleigh has continued his plans to build the hotel, using Smelterburg's work crew and that someone called 'The Mason' sabotages the work crew using the twins' own prank plans. The twins come across a laboratory and a Balm-like mixture which they presume belongs to 'The Mason'. It turns out the former head of local building company Smithy & Sons, Eugenia Smithy, was fired from the company for losing the job. and that she wanted to get the Smelterburg company kicked out so Smithy & Sons could get the job. The twins soon blackmail Eugenia into helping them sabotage the construction. In return she gets her job. Unfortunately, thanks to Eugenia, the twins' efforts backfire and the hotel work proceeds. ("Under Town")
When Mayor Knightleigh’s wife Judith attempted to remodel the Tower Mansion on live TV, Edgar had to defend the house alone since Ellen changed from a mischievous trickster to an apple-polishing ninny overnight by Pet's tears. Edgar’s plans to stop this house metamorphosis were stymied at every turn by his turncoat sister, and finally he loses all hope for her when he witnesses her going to Stephanie's for a sleepover. He eventually finds a cure for her, and a way to repel the invading army, but not before learning that Pet's tears is a stronger version of the balm. The twins were left with the unsettling realization that Pet has motives of its own, is an old friend of the towns founder Augustus Nod, as well as a possible alliance with their creepy caretaker, Heimertz. ("Pet's Revenge")
When the Heimertz Family Circus arrived to Nod's Limbs, Edgar and Ellen found kindred spirits among the odd performers and befriended a young band of mischief-makers, The Midway Irregulars. While hiding from an angry Heimertz, Edgar meets the escapit extrordinaire, Ormond The Impossible who too agrees that Heimertz is "unstable". Edgar decides he wants to become Ormond's apprentice and Ormond promises to make the twins join the circus if they can get three ambers for him that are hidden somewhere in the circus without anybody knowing about it. After finding the first amber, Edgar and Ellen sneak into Heimertz's tribunal, where they find out that their mansion is property of the Heimertz family. After Madame Dahlia busts Ellen cheating in one of the midway's games, she orders the twins and the Irregulars to go to her tent, where she tells them the story of Mad Duke to teach them that greed is no game.
While searching for the third and last amber, Edgar and Ellen sneak into Pollyanna's puppet house, where Edgar accidentaly loses Phoebe's flants. After the twins accidentaly destroy the puppet house, they are forced to hide in Madame Dahlia's tent, where they find out the Dahlia has been helping Heimertz hide from his family, therefore they believe her to be their enemy. After finding the third amber and giving it to Ormond, the twins then stayed to watch the escapist perform, although after Ormond locks himself in a syrup-filled tank, the Big Top starts collapsing (thanks to Stephanie) and Manny the Colossus carries the reluctant twins to safety. Edgar and Ellen are then confronted by the Midway Irregulars, who chew them out for supposedly being Ronan's accomplices, risking the Hei-Flyers' lives, destroying the puppet house, and losing Phoebe's flants before Imogen declared that the twins were "going to the dunk tank, and you [the twins] aren't coming out", before being forced to flee from Jens, Taryn and Officers Jibbers and Jabbers to the Black Tree Forest Preserve.
When the twins sneaked into the circus one last time to watch Ormond's funeral, they found Madame Dahlia and Heimertz, chained and locked in a gorilla cage. Madame Dahlia attempts to reason with the twins one last time but they don't listen until Heimertz finally speaks to them and tells them that Pet is dying and that they have to dig up the Balm spring before being hauled away with the circus. As the twins head for home, Ormond reveals himself to be alive. He confesses that he had lied to them in order to win freedom for the circus and that he has a new apprentice: Stephanie Knightleigh, much to the twins' anger. When they return to the mansion they find out that the Mayor is going to destroy it now that he had the property contract, thanks to Ormond. ("High Wire")
Edgar and Ellen race against time to save their home from the Knightleighs and collect the spring balm beneath the mansion to save the dying Pet. As Edgar and Ellen scheme of ways to hinder the destruction of their mansion, a mysterious will and testament of the town’s founder, Augustus Nod, resurfaces with a series of elusive riddles to answer the town’s oldest mystery: Where are the golden limbs from Nod’s statue? According to the will, whoever solves and discovers where the original prankster had hid his limbs will acquire all that he once owned, including the twins' mansion.
After solving the last riddle, the twins believe that the whole thing was only a prank from Augustus Nod and decide that if they couldn't save their house, they could save Pet and trick the Nod's Limbsians to look for the limbs at the cave where the balm springs were buried in but what they found wasn't the golden limbs, but a giant mass of hair with an eyeball, which the tiwns believed to be a relative of Pet's.
Everyone but the twins immediately fled the house, and the twins realized that the creature was actually an elderly man who, overjoyed at being liberated from the cave, hugged the reluctant twins, calling them "sweet" and "the most beautiful things [he has] ever seen". After calming down, the man revealed to them that he was actually Augustus Nod, the founder of Nod's Limbs. Soon after that Stephanie, Judith, and the Mayor Knightleigh confronted them. After Nod explained what happened, Stephanie attempted to cave the twins and Nod in. Fortunately, thanks to a freed Heimertz, the group managed to escape.
Nod regained his land and money ownership but despite being grateful to the twins for freeing him, Nod demanded that the twins abandoned his property due to his hatred for people. As they walked away, Edgar wondered what was in Thaddeus' tomb since nobody found his body. The twins find the golden limbs in Thaddeus's tomb and Nod, after having a talk with Pet, decides to make him and Ellen his heirs after all. ("Nod's Limbs")
After Edgar and Ellen were revealed to be the responsables of most of the mischief in town they were treated like heroes and everyone celebrate them. The twins are delighted by this but they also discover that pranking was no fun anymore if the people loved it. After the Prank You Very Much parade and Heimertz and Madame Dahlia's wedding everything starts to collapse and a lot of accidents occur, which injures many people and Nod's journals and letters from Benedict are stolen. Edgar and Ellen suspect of Stephanie, Eugenia Smithy and Blake Glide. They soon discover that it was neither Eugenia nor Glide since they only want to be mayor and not to know the balm's secrets. After the elections for the new mayor get ruined by a swarm of ferocious rats, the Nod's Limbsians grow to hate Edgar and Ellen as they believe the twins caused it all. There is another robbery of Nod's journals and letters and Edgar and Ellen finally finds out who is the robber and the person that creates all of the disasters: Stephanie. After she escapes, Edgar and Ellen leave Nod's Limbs for the first time in their lives to pursue Stephanie and retrive her balm bucket and Nod's equipment. ("Hot Air")
After weeks of traveling, Edgar, Ellen and Pet arrive to Frøsthaven, which the twins described as "a Nod's Limbs trapped in ice" since the villagers are just as cheerful and gullible as the Nod's Limbsians. The trio meet Stephanie's new ally, the mad hermit Uta Glögg, who attempts to kill the twins using her best friend, the Yehti, a relative of Pet since she believed the twins wanted to steal her "pudding" (Balm). The twins also reunite with The Midway Irregulars, who were hympnotized with the Yehti's tears by Stephanie and ordered them to kill the twins, although they were saved by Pet. After Stephanie and the Irregulars drain and destroy the balm spring of Frøsthaven, they escape in opposite directions and the twins were then forced to split up for the first time in their lives in order to find them. ("Frost Bites")
After several weeks traveling alone, Edgar developed the habit of talking to himself. When he arrived to Cougar Falls, he met the monster hunter Gristly Jefferson. Edgar lied about who he was and told Grisly that he was a monster hunter named "Sir Salvatore Shipsailington", although Gristly called him "Sally", with Gristly's help he attempted to feed the Midway Irregulars the antidote for ithune's tears but were unsuccesful. ("Split Ends")
Inventor: Edgar plans many of the twins' schemes and diagrams.
Edgar is tall for his age and scrawny, with short black hair matted flat into his head. He has pale-white skin, an angular face and wide, bulging eyes. Like his sister, he wears one-piece, striped footie pajamas with flaps on the back that were once red and white but due to years of not being washed they changed to grey and a rusty shade of red. He wore an oversized tuxedo for Heimertz and Madame Dahlia's wedding, but he still wore his pajamas under it.
Edgar is generally calm and confident in many situations, but tends to lose his cool when scores are far against him. Edgar tends to also be a little absent minded. He is deliberate and detail-minded, he will draw up blue prints carefully before acting. Both Edgar and Ellen love booby traps and pranks, and they typically burst out in song or verse. Even though they often fight, Edgar feels especially vulnerable if Ellen isn't with him. Edgar also seems to have more of a sensitive side than Ellen.
Edgar also exhibits signs of psychopathy as he has a manipulative and cunning nature, exceptional intelligence and enjoys other people's suffering.