Sometime later he returned with his pack to Beacon Hills at the behest of fellow Alpha Ennis to seek vengeance on Gerard and Chris Argent for the death of one of Ennis' Betas. Instead, Deucalion sought peace by meeting with local Alpha Talia Hale and then trying to meet with the Argent hunters.
The meeting with Gerard Argent was a trap and Deucalion was blinded. While still recovering, one of his Betas attempted to take over and Deucalion killed him. In doing so he learned that Alphas become stronger when they kill their own Betas.
He then convinced both Ennis and Kali to kill their packs and join him, creating The Alpha Pack. He also showed the Twins, Ethan and Aiden (who were Betas at the bottom of their pack), how to merge together. Consequently they killed every member of their pack, saving their Alpha for last, and joined his Alpha Pack.
When he returned to Beacon Hills to claim Derek and Scott for his pack, he wore dark glasses and carried a cane with a spearhead concealed beneath the red tip at the bottom.
After multiple skirmishes, the alpha's pack is disbanded and his eyesight restored as a way to weaken the Darach, Deucalion is given a choice to amend his ways or next there would be no mercy. He made up for his evil deeds by aiding Scott's pack as a spy and offered guidance to Scott when Gerard returned for revenge until he is mortally wounded by Tamora Monroe.
According to Ms. Morrell, who is a clinical psychologist and Druid emissary to Deucalion, he is on a "narcissistically psychotic" mission to form the "perfect pack" and, to that end, wants a True Alpha like Scott McCall to join him.
She says Deucalion's desire to possess Scott's uniqueness was in conflict with an equally strong desire to destroy Scott's potential to become a True Alpha by getting him to kill.
He quietly distracts Scott in the hospital elevator to keep the teen from seeking Isaac Lahey. He later strikes what appears to be the killing blow to a Mysterious Girl in the high school locker room. (Read More...)
We learn that Deucalion captured and held Boyd, Erica, and Cora Hale in a bank vault lined with Hecatolite depriving them of moonlight for four months and turning them vicious. He enlists Ms. Morrell to create a Mountain Ash barrier once Scott and Derek have broken into the vault, trapping them inside. (Read More...)
Deucalion explains to Derek how he accidentally discovered that killing one of his Betas allowed him to absorb their power. Once he became blind, one of his Betas felt he was no longer able to lead so he tried to kill him and take control. Deucalion bested him, killed him, and found that he became faster and stronger because of it. (Read More...)
At an abandoned mall he and his pack attack Derek's and Scott. He nearly forces Derek to kill Boyd until Allison shoots flash bolts to temporarily blind his pack. Later, at Dr. Deaton's, he kills the badly injured Ennis even though he is expected to make a full recovery. (Read More...)
In the motel, Scott hallucinates that Deucalion is standing outside with his mother. Deucalion states that Derek is dead and that Scott is the new Alpha. Due to these events, he is coming for Scott and "everyone he loves". In the final moments of the hallucination, Deucalion slashes Melissa McCall's neck with his claws. (Read More...)
Deucalion offers to tell Scott where Deaton is being held if Scott can take his cane from him. Scott fails. Deucalion gives him a stab in the shoulder and a cryptic clue, saying he should "follow the current". (Read More...)
Sometime in the past, Deucalion had requested a meeting with Gerard to discuss peace between the Argents and the packs. After being blinded by Gerard, he learns from Deaton that his sight would not return. A beta of his, Marco, attacks him, but Deucalion shifts and kills him. (Read More...)
Deucalion and Kali arrive at the hospital with the intent of killing Jennifer Blake, who Kali reveals to be her former emissary. The two bicker over their choices involving Scott and Jennifer. After a night of battle, Deucalion offers Scott aid in saving his mother and Sheriff Stilinski from the Darach. Scott leaves with Deucalion. (Read More..)
Deucalion and Scott join the other Alphas to capture and kill Ms. Morrell. When she tells Kali and the others that it was Deucalion who killed Ennis, he attempts to play it off as the desperate lie of a woman about to die. Deucalion then stabs Morrell with his cane to shut her up. (Read More...)
He shows his true face and his real motive for everything this season. After easily defeating Jennifer Blake, he tries to force Scott to kill her. Jennifer restores his eyesight. (Read More...)
He sends Braeden to save Derek from a group of hunters. (Read More...)
He subtly encourages Hayden to go help her friends. (Read More...)
Deucalion reveals that he allowed himself to be captured. Then he shows Theo how to steal power. According to him, the secret to stealing power is to "take their pain, take their life, take their power". (Read More...)
After being betrayed by Theo, Deucalion warns him that his willingness to stab anyone and everyone in the back will be his down fall. Its later revealed that he isn't really blind and that he's been working with Scott the entire time. (Read More...)
Deucalion refuses to join Scott and Malia in their fight against Gerard. He is no longer a killer, and has chosen the path of least resistance, which is demonstrated in his schooling of Malia. (Read More...)
As he lies dying, holding Scott's hand, he tells the werewolf that Gerard's worst fear is that he will never beat him. (Read More...)
The character is named after a son of Prometheus, a Noah like character in Greek mythology.
- “I'm aware of a certain potential threat. But then someone once taught me a very smart way to eliminate threat- get someone else to do it for you."” — Deucalion to the mystery girl in Tattoo
- “Is everybody done? 'Cause just listening to that was exhausting." ” — Deucalion after Ennis and Kali subdue Derek and Cora in Unleashed
- “I'm a man with far more vision than simple murder. In fact... I'm here to show you just how much vision a blind man can have.” — Deucalion to a wounded Derek in Unleashed
- “Know me? You've never seen anything like me. I am the Alpha of Alphas. I am the apex of apex predators! I am Death, destroyer of worlds! I am the Demon-Wolf!” — Deucalion's speech after Derek calls him a fanatic in Unleashed
- “Come on, Scott, put those away. I’d have to be blind, deaf, and quadriplegic for you to be an actual threat. Or maybe you should take a chance. Your heartbeat’s steady. You might be afraid of me, but you’re controlling it. Maybe you’d actually rise to the occasion, become an Alpha by killing one."” — Deucalion to Scott in Frayed
- “So now I'm coming for you. You and everyone you love. I'm coming for all of them!” — Deucalion in Scott's hallucination in Motel California
- “I had a vision, a vision of peace.” — Deucalion to Gerard in Visionary
- “You did it to be with Ennis, so don't point that accusing toe at me.” — Deucalion to Kali in The Overlooked
- “I'll kill any living thing that gets in my way.” — Deucalion to Scott in Alpha Pact
- “The lies people will tell when they're begging for their life.” — Deucalion to Ms. Morrell in Alpha Pact
- “Are you ready Jennifer? Hmm? Have you gathered your herbs? Prayed to your ancient gods and your oak trees? Slit a baby's throat perhaps? Should we show them why you needed to sacrifice 9 innocent people just to face me? Or is it 12 now?” — Deucalion to Jennifer when he is shifting in Lunar Ellipse
- “I think you'll be surprised of what a good team we make.” — Deucalion to Scott in Lunar Ellipse
- “The Beast of Gévaudan. History's most vicious, most famous werewolf. And you think I'm going to show you how to steal its power?” — Deucalion to Theo Raeken in The Sword and the Spirit
- “Feel that Theo? That's the secret to taking power, pain. Take their pain, take their life, take their power. Its all or nothing. You take until there's nothing more to give, that's where you find the spark of power and then you take that as well. Pain, life, power, in that order and only that order” — Deucalion to Theo Raeken in The Beast of Beacon Hills
- “You know Theo, someday your willingness to stab anyone and everyone in the back might turn out to be your downfall” — Deucalion to Theo after being shocked by him in Apotheosis