|“|| Boyd: "It's okay..."|
Derek: "No, no... No, it's not... it's not..."
Boyd: "It's all okay, Derek..."
Derek: "I'm-I'm sorry."
Boyd: "The full moon? That feeling? That was worth it. There's a lunar eclipse... I always wondered what... what that felt like for one of us... one of us..."
Boyd was the third and final person Derek had bitten and turned with the intention of adding to his new pack shortly after becoming Alpha. Though Boyd seemingly only agreed to the transformation out of a desire for friends, as he was an outcast in school, he eventually grew to care for Derek and his fellow Betas, Isaac Lahey and Erica Reyes. Derek seemed to value Boyd's silent, observant personality and relied on him as his lieutenant for many of their missions, including the standoff between them and the Argent Hunters in Season 2's Raving.
However, the stresses of being a Werewolf in Beacon Hills at the time (namely the threat of the aforementioned Argent Hunters and the string of violence and murder committed by the Kanima and its master) that Boyd, along with his best friend Erica, decided to leave the pack and seek out another to join in an area that wasn't under so much pressure. Unfortunately for them both, this resulted in them being first kidnapped and tortured by Gerard Argent before being released and then caught and held captive by the Alpha Pack as a way to manipulate Derek, who they wanted to join their ranks.
Despite Boyd leaving the pack, Derek never gave up on looking for them and was willing to do whatever it took to get him and Erica back safely, even if it meant risking his own life; though Derek did survive the rescue, he did get trapped in the bank vault by Marin Morrell and her Mountain Ash and was mauled by the feral Boyd and his long-lost younger sister Cora, who was held captive with Boyd and Erica by the Alpha Pack. Boyd was devastated by the death of Erica at the hands of the Alpha Kali but still rejoined Derek's pack upon returning to the fold.
Boyd continued to be a loyal packmate and Beta to Derek, even as Scott McCall, a recently revealed ascending True Alpha, began to attract his packmate Isaac toward his own pack. He proved this when he and Isaac skipped school upon learning that the Alpha Pack intended to confront Derek at his loft that night; it was Boyd who came up with the idea to flood Derek's loft and use electricity to either weaken or kill the Alphas upon their arrival to the apartment, and this plan would have worked if the Alphas had not been tipped off and cut the power prior to entering.
Though Derek forbade Boyd or Isaac from interfering with his fight with Kali, Boyd was unable to hold back when he saw Kali getting the upper hand, which resulted in him being electrocuted when Stiles, Lydia, and Cora arrived to turn the power back on. The furious Kali then forced her fellow Alphas Ethan and Aiden to hold Derek's clawed hands while they impaled Boyd with them, causing Derek to involuntarily steal Boyd's power and ultimately take his life, as the electrical shock kept him from healing as he normally would. While Derek blamed himself for Boyd's death, Boyd assured him that it wasn't his fault and made it clear that his time as a Werewolf made his life worth it. The guilt Derek felt as a result of losing Boyd (as well as losing Erica earlier in the season) is what ultimately drove him to sacrifice his Alpha spark to save his sister Cora's life after she was poisoned with mistletoe, reverting him back to Omega status.
In Ice Pick, Derek had killed his uncle Peter Hale and stolen his Alpha powers, becoming an Alpha himself. Unbeknownst to anyone but Derek himself, he was building a pack for himself to help him stand against the Alpha Pack members who were heading to Beacon Hills to recruit him. He turned the abused teen Isaac Lahey and the epileptic Erica Reyes into Werewolves, only needing one more Beta to complete his pack. Boyd seemed perfect for the last spot due to him lacking many friends and having the habit of eating lunch alone, so Derek offered him the Bite.
Knowing that then-Omega Werewolf Scott McCall would likely interfere in his plan to turn Boyd, Derek, accompanied by Erica and Isaac tracked down Boyd and Scott to the high school, confronting them at the ice rink, where Boyd worked. Derek asked both Boyd and Scott to hear Erica and Isaac's opinions about being a Werewolf. Erica and Isaac lunged for Scott and battled against him, but since Scott had been a Werewolf much longer than either of them, he had more experience and defeated them easily before sliding them across the rink.
Derek joined the fight and wiped the floor with Scott thanks to his heightened Alpha powers to make Scott understand that he shouldn't meddle in the personal decisions of his Betas. Boyd approached the bloodied Scott to reveal that he had already gotten the Bite from Derek but prefered to be a Werewolf like Scott rather than one like Derek.
In Party Guessed,
In Master Plan,
In Chaos Rising,
In Visionary, Derek disappeared and was not seen since Boyd's death. At the end of the episode, he was seen in the Abandoned Distillery, his favorite spot where he used to hook-up with his teenage girlfriend Paige Krasikeva. He was staring with grief at the spiral that Ennis carved into the wall with his claws, implying he was intent to get his revenge on the Alpha Pack for killing Erica and forcing him to kill Boyd.
In The Girl Who Knew Too Much, Derek met with Jennifer for the first time since Boyd's death. She initially was mad at him because the "I needed to be alone" was the worst excuse ever but realized that he was still mourning Boyd's death and backtracked her comments. She insisted that she hadn't felt safe, especially when Ethan and Aiden were walking around the school like they had nothing to do with the death of one of their fellow students. Derek assured her he wouldn't let the twins or the rest of the Alpha Pack harm her and asked her to return to the loft with him, but she refused, saying she not only had three more class to give but she also was organizing a recital to honor those who died the last weeks. They kissed one last time before they parted ways.
In The Overlooked, Jennifer, revealed to be the Darach commiting human sacrifices through Beacon Hills, was stuck in an elevator in Beacon Hills Memorial Hospital with Derek after the Alpha Pack members, who invaded the hospital to kill Jennifer, forced Melissa McCall to shut down the power to the hospital. Jennifer confessed that she made oaths with the different human trios to "loan" her their power so she could make the Alpha Pack pay for their crimes against the human population and that their actions would never be overlooked like she was. Derek insisted that the Alpha Pack couldn't be beaten but Jennifer was reminded of Boyd asking Derek what would happen to a Werewolf during a lunar eclipse. Although Derek did not have the time to tell Boyd before he died, he knew the answer. When asked the question, Deek reluctantly admitted that Werewolves would lose all their powers for the duration, which seemed to be Jennifer's plan to take down Deucalion and the other Alphas.
In Alpha Pact, Isaac and Derek managed to take Cora back to the loft, where she was still suffering and dying from the effects of the Mistletoe that Jennifer used to poison her. When Derek had no idea if she was dying nor what to do to save her, Isaac blamed Derek for bringing Jennifer into their lives and ranted on his impulsivity and hotheadedness that had only put their pack in danger, referencing how it resulted in the deaths of both Boyd and Erica, the possibility of Cora being dying, and Derek was not doing naything to help anyone.
Isaac began leaving the loft, intent in helping the future McCall Pack members in rescuing Melissa and Sheriff Stilinski from Jennifer's clutches, adding that Derek could stay there and "perfect the art of doing nothing" before he left for good the Hale Pack, contributing to Derek's grief and awareness that he had been a terrible leader and Alpha to those around him.
Overwhelmed with grief and guilt over how he put his packmates in danger because of his pursuit for more power, Derek ignored Peter's warnings that his Alpha powers were his power to fight back against Kali and decided to perform a ritual that would allow him to transfer his Alpha spark to Cora so she would have enough power to heal from the mistletoe.
- Though Boyd was the third and final person Derek turned in order to join his pack, he was the fourth of five people Derek had bitten during his short time as Alpha; Derek had bitten Jackson Whittemore immediately after stealing Peter Hale's Alpha powers with the hope that the bite would kill him, and he inadvertently bit Victoria Argent while trying to save Scott McCall from her, though he knew she would never be part of his pack.