Gideon Emery as Deucalion -Werewolf-
Deucalion is an Alpha werewolf, formerly the Alpha Pack leader and one of the main antagonists of Season 3. In the past, Deucalion was the leader of his Pack and his Emissary was Marin Morrell. Deucalion had come to Beacon Hills for a meeting to discuss the threat of the Argent werewolf-hunter family. Fellow Alpha Ennis wanted help to combat the Argents because they had killed one of his Beta werewolves. Deucalion reasoned saying they killed his wolf because he killed two of theirs. Ennis declared revenge, anyway. Deucalion wanted to avoid bloodshed to make peace with the Argents. He met with Alpha werewolf Talia Hale and her Emissary, Dr. Alan Deaton to seek their advice before meeting with Gerard Argent. He and three of his Pack members were instead tricked and ambushed by Gerard, who not only killed Deucalion’s Betas, but his own men who wished for peace with the Packs. He later blinded Deucalion in an unsuccessful attempt to kill him.
With the help of Deaton, Deucalion’s eyes healed physically, but his sight didn’t return. This discovery coupled with Gerard’s betrayal enraged Deucalion. Marco, another of his Betas, took this opportunity to try and kill Deucalion to become the Alpha werewolf of their pack. Deucalion, however, realized he could see using his werewolf eyes and killed Marco in retaliation. In doing so he realized Alphas became stronger when they kill their own Betas. The entire experience corrupted Deucalion. Eventually he killed the rest of his pack to add all of their powers to his own and lead fellow Alphas Kali and Ennis to do the same. Sometime after, he came across the twins (Aiden and Ethan) who were “the bitches” in a brutal Pack. Deucalion taught them how to control their merged form to fight back against their abusers and they joined him after killing their original Alpha. He pulled all five of them together to form an Alpha pack. He even had all the members kill their Emissaries, except for Marin, his own. Deucalion eventually came to be known as ‘the Demon Wolf’.
Deucalion’s Alpha Pack arrived in Beacon Hills in the Season 2 finale, capturing Boyd and Erica in the process. In “Unleashed”, Deucalion goes to Derek’s loft along with Kali and Ennis to offer Derek a proposition for Derek to kill his own Pack to join his own with the intention of recruiting him. Deucalion’s actual plan for Derek was to place him against Scott. To this end, after the battle between the Packs in “Frayed”, Deucalion kills Ennis after he fails to heal himself, absorbing Ennis’ power; he lies to Kali and the twins that Ennis died of his wounds, intending to have a vengeful, distraught Kali force Derek’s decision to join the Alpha Pack. In “Currents”, the reason for this is because Deucalion knows that Scott has the potential to become a True Alpha and wants to recruit Scott, not Derek. Deucalion’s true intentions throughout Season 3 were to push Scott into a position to either join the Alpha Pack or have Scott kill somebody destroying his True Alpha potential eliminating Scott as a potential threat to him, and also having Ethan and Aiden enroll in high school to seduce people close to Scott for leverage. When the new killer committing human sacrifices is revealed to be a Darach, Deucalion had his pack hunt it down. He targets the Darach because it used to be a druid who can call upon powers from sacrifices. After finding out that the Darach is Jennifer, Kali’s old emissary, the Alpha Pack leader tried to have her killed. Scott later tearfully joins Deucalion’s pack in “The Overlooked” in return for Deucalion’s offer to help look for his kidnapped mother. In “Alpha Pact”, he tries to have Marin killed when he suspects her to have had a role with the human sacrifices and she confirms to have had been working against him to “maintain balance”, but Scott ultimately saves her. In “Lunar Ellipse”, Deucalion and Scott face off against Jennifer and Derek (who Jennifer forced into helping him). Deucalion shifts into his Demon Wolf persona and overpowers both of them easily. He then tries to force Scott into killing Jennifer to become an Alpha, but Scott blinds him using flash bolts as he can see as a wolf. During the lunar eclipse, Deucalion temporarily loses his powers and Jennifer is to be able to defeat him. After being beaten to a pulp, Jennifer is tricked by Derek into healing Deucalion’s normal eyesight to allow him to see her face and the result of his crimes on her but Jennifer is weakened because of this. After the lunar eclipse passes and Scott awakens his True Alpha powers by breaking through Jennifer’s mountain ash barrier, Deucalion saves Scott from becoming a killer to stop Jennifer from sacrificing the kidnapped parents by doing it himself, slashing her throat. Derek and Scott decide to let Deucalion go giving him the chance to redeem himself on the condition he tries to maintain peace between werewolves and humans.
In the episode, “More Bad than Good”, it is revealed Deucalion had hired the mercenary Braeden to rescue Derek from the Calavera werewolf hunters. His current whereabouts are unknown.
Originally, Deucalion was described as a “man of vision” in the past, a level-headed, reasonable person as an Alpha, the leader of his Pack with a belief and faith in humanity. He was changed by Gerard Argent’s treachery and monstrosity during his proposed piece offering between the Packs and the Argents, the loss of his sight and his discovery of subsuming the powers of his Pack members by killing them. Nowadays, Deucalion is sociopathic, obsessive, vain, charismatic, power-hungry, willing to kill anyone who gets in his way, and not above killing members of his Alpha Pack (which he does to Ennis), if they are useless to him. It remains to be seen if he will change, as Scott and Derek gave him a second chance. Deucalion possesses abilities far greater than that of an average Alpha werewolf, that he is able to command a Pack of exceptionally strong Alphas with both fear and respect. Unlike most werewolves, in his transformed state his skin turns dark blue/grey and his facial structure changes making his appearance more demonic than wolf-like. His strength and speed are so immense that he easily bested both Jennifer, powered by the Nemeton, and Derek without any damage and appeared as a blur during his movements. Deucalion has the special ability to mask his scent as Scott couldn’t identify him as a werewolf when he first encountered Scott. He also has the ability to force other werewolves to shift with a powerful roar.