In Tattoo, Scott was in the elevator at Beacon Hills Memorial Hospital, trying to find Isaac Lahey's room, when he was joined by Deucalion, who appeared to Scott as a human blind man wearing sunglasses and using a cane to feel his way around. Deucalion politely asked him to push the button for the second floor, which Scott had already pressed, and the two stood in awkward silence until the elevator doors opened to their destination. Scott was just about to rush out when Deucalion asked him for help in guiding himself out, and before he could decline, Deucalion placed his hand on his shoulder and squeezed it, forcing Scott to reluctantly lead him down the hallway. As he did so, he sighed and drooped his head, as he was in a hurry to find Isaac before his accelerated healing ability drew suspicions from the hospital staff.
Later that evening, when Scott and Stiles Stilinski uncovered the Alpha Pack symbol painted on the front door to the Hale House ruins, Derek Hale had no choice but to admit that a pack of Alphas was in town and that they had captured Vernon Boyd and Erica Reyes, whom Derek, Isaac, and Peter Hale had been trying to locate for the last four months. When asked how an Alpha Pack even worked, Derek informed Scott and Stiles that the pack had a leader named Deucalion.
Meanwhile, at Beacon Hills High School, a mercenary named Braeden who had rescued Isaac from the Alphas and was trying to get in contact with Scott to warn him about the incoming danger, fought against the rest of the members of the Alpha Pack (Kali, Ennis, Ethan and Aiden) until was incapacitated. Once she had fallen to the ground to nurse her injuries, Deucalion approached her, leading Braeden to reveal that she knew he feared Scott and "who he would become." Deucalion tried his best to appear unfazed and pointed out that while he was aware of Scott's potential, he was taking the advice of someone he knew in dealing with the threat; namely, he planned to have Derek take care of Scott for him, implying that one of his plans was to have Derek kill Scott as part of his initiation into the Alpha Pack if Scott refused to join them himself.
In Unleashed, Ethan and Aiden, twin members of the Alpha Pack, began to attack Scott and his close friend Isaac Lahey in retaliation for pranks that the two (with help from Allison Argent) had played on them. Suddenly, they were interrupted by Deucalion, who forced them to stop and silently punished them by lashing them both across the face with the small blade at the end of his cane. The twins then somberly followed Deucalion out of the school in a submissive manner, indicating the level of authority Deucalion held over them. When Isaac looked over at Scott with concern and asked him who the man was, Scott explained that he was Deucalion, the Alpha of the Alpha Pack.
In Frayed, Scott, who had just learned about Allison's role in helping them trap the wild Boyd and Cora during the last full moon in Fireflies, warned her against getting involved with the Alpha Pack, describing them as more dangerous than anything they had faced at this point in time. Afterward, he got into the elevator in the hallway outside the Argent Apartment, where he found Deucalion waiting for him.
Scott flicked out his claws in anticipation of a fight with the Alpha, but Deucalion just chuckled and advised him to "put those away," remarking that he would have to be blind, deaf, and quadriplegic in order for Scott to be a threat for him. After a moment, Deuclion rescinded his earlier comment, conceding that he could tell by Scott's heartbeat that he feared him but was controlling it, which meant he could potentially rise to the occasion and become an Alpha by killing one. Scott insisted that he wasn't like Deucalion because he didn't need to kill people, to which Deucalion reminded him that sometimes, people are put in the position where they have to kill one person in order to save another.
Scott, visibly frustrated, asked Deucalion if threatening him was the reason why he was there, but Deucalion replied that he was there because he lived in the building, describing the apartment complex as great and with very friendly neighbors. Finally, Scott asked Deucalion what he wanted, and Deucalion responded that he wanted to see what Scott is made of before the elevator doors opened on the ground floor, forcing Scott to leave so that other tenants could enter.
Immediately after this confrontation, Scott went to Derek's loft to inform Derek of what he just learned, though he was shocked to find that Peter, Cora, and Boyd were also at the apartment with Derek as well. Scott was also surprised to learn that the Hale Pack already knew that Deucalion and the Alpha Pack were living in the Argent's apartment complex, as Boyd and Cora followed Ethan and Aiden home one day after school. When Scott pointed out that this meant that Deucalion wanted them to know where they lived, Peter remarked that it was more likely that they just didn't care either way. Scott then noticed that they seemed to be looking at schematics for the building and asked them what they were doing, forcing Peter to admit that "the schemers were scheming" and that they were planning a preemptive strike against Deucalion and the Alpha Pack before Derek insisted that Scott would be helping them.
Scott and the Hale Pack then got into the details of the plan, as Derek informed them that Deucalion and the Alphas lived in the penthouse apartment right above Allison. When Scott seemed exasperated by the fact that the others wanted to kill the Alphas first and stated, "Why is the default plan always murder? For once, can someone try to come up with something that doesn't involve killing everyone?", Peter stated that, while he believed Scott to be "blandly moral," he didn't disagree with his assessment that it was not a great plan. Derek argued that they could sit back and wait for Deucalion to make the first move against them, but Scott maintained that they couldn't beat a pack of Alphas. Cora interjected that this was why they only planned to go after Deucalion, with Boyd adding that by cutting off the head of the snake, the body would die.
Unconvinced by the Hale Pack's assessment of the situation and unwilling to risk any of his friends getting hurt in the coup d'etat, Scott secretly arranged a meeting with Deucalion to try to come up with a diplomatic solution to their problem, though he was unable to talk Isaac out of coming with him. Scott and Isaac then arrived at the Abandoned Mall where they had arranged their meeting, only for it to be revealed that the Hale Pack, expecting Scott to try to talk sense into Deucalion, had followed him there to take advantage of the fact that the Alpha was alone. Unfortunately for them all, Deucalion had brought the rest of the Alpha Pack with them as back-up, and a large-scale fight ensued.
The Hale Pack was quickly incapacitated by the Alphas, who turned to Deucalion for their next move. Deucalion ordered Derek to kill Boyd, who had been badly injured by Ennis, and when Derek was reluctant to do so, Kali exasperatedly asked if Deucalion was serious about Derek, who she described as a "kid" who was an Alpha to "a couple of useless teenagers," though Deucalion looked directly at Scott and stated that some had more promise than others in a hint that he knew about Scott's potential to become a True Alpha. Just as Kali, wanting to force Derek's hand, gave him an ultimatum (either Derek could kill Boyd, or she would kill Cora), Allison arrived and began shooting flash-bang arrows at the Alphas, leading Deucalion to order everyone from both packs to cover their eyes, not wanting them to suffer the same fate as he did with regards to his blindness. This distraction gave the Hale Pack and Scott to get their wounded out of harm's way before reengaging in a fight that ultimately ended with both Ennis and Derek presumed dead after they tumbled over a ledge and fell three stories before landing on the escalator below.
In Currents, Deucalion is found in the musical room by Scott. He knows about Deaton's disappearance. So he decides to make a test: if Scott take his cane, he'll know where's Deaton. Scott fails but Deucalion gives him a clue "Follow the current". Deaton is rescued and tells Scott that Deucalion is going after Scott, instead of Derek.
In The Overlooked, Deucalion asks Scott to join his pack so he'll find Stiles' father and her mother and he agrees
In Alpha Pact, As Mrs.Morrel gets surronded by the Alpha Pack ,she tells Scott to go back to his friends which makes Deucalion say that he decides what he wants for himself and then she tells that Deucalion was trying to create the perfect pack by killing a lot of his betas and including Ennis she says that Deaton saved him but Deucalion killed him to force Kali go after Derek but Deucalion states she's lying.
In Lunar Ellipse, Scott along with Deucalion fights Jennifer and Derek and Deucalion forces him to kill Jennifer but Deucalion was blinded by Scott, he loses all his powers thanks to the Lunar Eclipse and gets his sight healed by Jennifer, as the eclipse is over, Jennifer protects herself with a mountain ash barrier but Scott breaks it and reaches to his True Alpha status in the process. And Deucalion lives.