|Taken Name||Walden D'Essai|
|Magic||Unknown before knowing his True Name|
Argeddion (also known as Walden D'Essai) is a Mage that had discovered his True Name. Being a pacifist, he believed in peace and attempted to use his powers to make everyone in the world magical - his vision of a peaceful world, which he thought would bring the human race into a new plane of existence. He was an immensely powerful sorcerer, with the same power level as Darquesse.
As Walden D'Essai
Argeddion, then known as Walden D'Essai, was a Mage searching for a way to make the world peaceful. During his studies, he discovered his True Name. During this time, he was dating Greta Dapple.
Because he discovered his True Name, Tyren Lament, Vernon Plight, Lenka Bazaar and Kalvin Accord retrieved him and placed him under an enforced coma. The group then traveled to the Himalayan Mountains to keep Argeddion out of harm's way.
In the Alps
Whilst in a coma, Argeddion transferred a portion his magic to mortals across the world, believing if everyone had magic the world would be perfect. He also manipulated Tryen and the group during his time in a coma, as he was able to frequently use his subconscious, despite his state of imprisonment.
He also gave of his magic to Kitana Kellaway, Doran Purcell, Sean Mackin and Elsie O'Brien, with the latter leaving the group and lamenting her powers. He later controls Silas Nadir into leaving an Echo on Valkyrie Cain, for the sole purpose of dragging her into a parallel dimension, to bring him his "surprise guest".
After Fletcher teleported the Cube to the Accelerator in the Irish Sanctuary, Argeddion, unable to wake himself up from his coma state, controlled the minds of Tyren, Kalvin, Vernon and Lenka for years, and had made them come under his influence, making them generate an impenetrable force field around the Accelerator. This separated them from the other mages and sorcerers intent on shutting the Accelerator down, allowing for nobody to be able to interfere with his awakening.
Argeddion is next seen when Skulduggery and Valkyrie lure him into their presence by confronting Greta. He brings her to safety, then moves right above the Accelerator as Skulduggery instructs. The Accelerator then shoots a beam of magical energy that manages to keep Argeddion in the one spot. However, he summons magic and launches his one beam of energy back through the Accelerator, destroying it and injuring a lot of the mages powering it.
Kitana, Doran, and Sean then attacked Argeddion, in which he seemed to be defeated simply because he did not use any of his magic to defend himself or to attack. The trio then attack the other Mages present around the area.
Kitana then kills Greta when she tries to make them stop attacking him. In his anger and sadness, Argeddion shatters every mental block in the area, including the one he placed around Darquesse in Valkyrie's mind, causing her to escape from the psychic blocks of which he set up within Valkerie's mind. Skulduggery also finds the case with Lord Vile's armour nearby, Argeddion having hidden it in a shed.
Valkyrie and Skulduggery fly back to the Sanctuary, where Kitana, Sean and Doran are attempting to put Argeddion back into the device that held him in a coma, just so they can keep their powers. Valkyrie and Skulduggery attack them as Darquesse and Vile, battering them repeatedly, yet they refuse to stay injured. Darquesse finds Argeddion feeding them power, but severely reducing his own, making him weaker than her. Darquesse comments that he is feeding them all his “lovely, lovely, power” and then attacks him. He uses his power to fend her off and she comments that “even that took a lot out of him”. Argeddion is horrified to learn that she can already see magic, revealing that it took him months before his eyes started to adjust. Darquesse then starts breaking down Argeddion's defences, but before she quite manages it, Argeddion boots the power of the echo shunt inside Valkyrie. Once in the other dimension, he goes to find his other self.
When Darquesse returns from the other dimension, she kills the Kitana, Sean and Doran in a fit of rage by destroying their heads. Argeddion‘s power then returns to him from their dead bodies, and Argeddion brings the three children back from the dead. Darquesse wants to kill him, but knows that Argeddion with all his power back is “far beyond even her now”. Argeddion reveals that he has taught his alternate version's true name to him and intends to give everyone in the world magic with Walden’s help. However, his counterpart refuses to cooperate with his plan, having experienced a world where magic is known to mortals, and where the sorcerers are evil, and the mortals are kept in rural villages, down in the gutter. When the Alternate Walden tries to force Argeddion to send him back, they have a fight. Darquesse watches the magic with her aura vision, commenting on Argeddion‘s violent animal instinct, which resulted in Argeddion accidentally killing Walden, an ironic outcome considering Argeddion’s insistence that the best of humanity could prevail. Darquesse decides that her only chance to kill him is while he is distracted over the death of his alternate self. However, both she and Argeddion are knocked unconscious by Skulduggery Pleasant moments later. Skulduggery explains that while they have the power of gods, their minds are still human. He uses the lights to flash a rhythm, inducing a epileptic seizure in Argeddion and Darquesse. He is last seen having is memory wiped, and having his true name sealed off to him, in order to be 'reborn' as a mortal.
While he was under the impression that he was a teacher and had no inclination of the magical world (due to Deacon Maybury), Darquesse comes to him pretending to be a friend of some of his students. She breaks down his memory walls by shoving a Remnant in him. When she was done, she rips it out of his throat, and digests it, along with Argeddion’s memories and knowledge on how to track magic. She blasts a thin laser beam the size of a pencil through Argeddion’s heart, killing him.
In the other dimension, Walden is living in the city of mages. He is helping the fabled Resistance movement by controlling one of the secret ways in and out of the city- the sewer. Skulduggery, Valkyrie and Serpine wait until he enters his house, disabling all the alarms, before breaking in. He shouts at them, telling them to leave. One of his neighbours calls an authority, who knocks on his door and asks him why he’s making noise. Walden is understandably nervous, as answering wrongly may get him killed. After the official leaves, he agrees to help the trio.
Argeddion is noted to be a pacifist by many people in the book. Although he has vast magical abilities at his disposal, he has never used them to harm or kill anyone (except for his alternate counterpart, which was purely accidental). However, he has been indirectly responsible for many deaths, as by giving powers to Kitana, Doran, and Sean, he allowed them to go on a killing spree, using his magic to run wild. He also refuses to see anything but good in his actions, and is a little naive, hoping that everyone will share his wish for peace and love.
After discovering his True Name, Argeddion develops unlimited powers. He has the ability to control people, even whilst in a coma. He also had shown the ability to give a portion of his magic to anyone, able to retrieve it when he wished. He even had enough power to destroy a machine channeling dozens of powerful sorcerers' energy, and quickly recover.
After awakening from his coma, Argeddion discovered that he could manipulate any form of magic after experiencing it once. This is true, as he copied Fletcher's Teleportation ability and Silas' Dimensional Shunting after experiencing each technique once.
However, Argeddion did not use his amplified magic abilities for combat, as he was a pacifist. He also showed that he can use his magic to heal himself rapidly, as well as revive the deceased Kitana, Doran and Sean.
Like Darquesse, he has the ability to see magic, and 'other things too' he noted, due to knowing his True Name for a longer period and studying magic more. However, Darquesse is shown to grasp magic at a faster rate than him, learning how to see magic in a matter of weeks as opposed to the months that it took Argeddion.
After he re-absorbed his own magic from Kitana and her allies even Darquesse admitted that she was no match for someone with his power.
Argeddion admitted that if Skulduggery had embraced Lord Vile he may have been able to stop him early in his path to change the world. However, this is only because of Lord Vile’s willingness to use violence, and Argeddion’s refusal to harm anyone, even in self defence.