In The Garden, his corpse is seen after having been dug up by Orlando and used as part of his chess game along with Doctor Colin Benson. A devastated Hope mentions that Dev was her friend.
In Hesperides, in flashbacks, Dev is brought by two other Disciples to Skyring to be punished for an unknown crime. Armed with a small rake, Hope chases Dev away from the cabin though he is visibly impressed with the young girl and her courage. Dev later returns, tosses Hope some seeds and ignores her instructions not to eat a plant, causing him to get sick. Hope lets Dev in the cabin and treats his illness before noticing the counter on his arm. Dev informs Hope that its counting down from 10 years and until that time is up, its just the two of them. Upset, Hope runs off to cry and Dev follows her and comforts the young girl. Hope tells Dev that she needs to save her mother and Auntie O. Over the next ten years, Dev raises and trains Hope as much as he can, but as Dev is only a Level 7, the two are left concerned that Hope won't be able to provide the answers she will need if she is stopped by anyone of a higher level than Dev.
With about 2 and a half days left on Dev's clock, Hope and Dev begin preparing for their rescue mission with Dev painting Disciple tattoos on Hope's face and going over their plan with her. When the time comes, Dev attacks the Disciples, killing two, but is stabbed through the back and mortally wounded by a third that cloaks. Dev kills the Disciple with his own grenade and dies in Hope's arms, forcing her to continue on without him. With his last words, Dev orders Hope to save her family.
In the present, Hope references her time with Dev while preparing a similar plan for when the Disciples return for Orlando. Later, when Hope draws Orlando out by pretending to be drowning, he is playing chess again with his group of corpses, including Dev. During dinner with a now-saner Orlando, Hope tells him about how Dev trained her as much as he could and that she failed because she hesitated to kill when the time came. Hope blames herself for Dev's death and comments that his body is at your skeleton picnic." Orlando gives Hope his condolences and promises Hope that he will bury Dev's body with honor much to her gratitude.
Almost 5 years later, as he marks Hope as a Level 12 Disciple, Orlando tells Hope that Dev would be proud of her like Orlando is.
In Welcome to Bardo, in a flashback to 31 days before the present, after Hope rescues Octavia, Levitt realizes that she triggered a biohazard alert to keep people away from the Stone room and calls it clever. Hope admits that it wasn't her idea but Dev's. After confirming that the retrieval team sent for Dev isn't coming back, Levitt warns Hope that she only has 30 minutes before the Disciples send another one which Hope already knows thanks to Dev who "knew everything." Hope tries to activate the star map to send Octavia back to Sanctum and is confused when she can't turn it on like Dev said. Commenting that "unlike Dev, I actually do know everything," Levitt activates the Anomaly for them.
In a flashback to a week before the present, Anders warns Captain Meredith to be careful as Hope was able to turn a Level 7 Disciple, Dev, against them. Arguing with Anders over prioritizing individuals over the collective, Hope states that it's called love and it is the reason that Dev turned against his own people.
In The Flock, after taking down Disciple trainees, Hope mentions to Anders that she was trained by a Level 12 Disciple, Orlando. Anders brings up the fact that she was also trained by a Level 7, Dev. Later, while arguing with her mother, Hope tells Diyoza that Dev was like a father to her, prompting Diyoza to bring up Hope's real father.