Mr. Jake Delvin is a music teacher, an replacement of Mrs. Felson and an main villain in Fred 2: Night of the Living Fred. He was responsable to disappears Mrs. Felson and was suspected to be a vampire. He is plortryed by Sett Morris.
Fred arrives home screaming and shares his flashback with the audience. The day prior, Fred went to music class to play Fur Elise, and his favorite music teacher Mrs. Felson, who has trouble hearing, told him that he plays beautifully. The next day he comes in to play, expecting Mrs. Felson, but finds out that she has been replaced by a Mr. Devlin . He then sees Mr. Devlin cleaning up and throwing away a hearing side, which makes Fred suspicious. Later he is walking home with Bertha and sees a girl named Talia following them. Believing that he is being stalked, he runs home screaming.
The next day at school, Devlin encourages students to "Join the World of Music," a music appreciation club. However, Fred thinks that Devlin is trying to turn students into vampires, and to his horror everyone takes the lessons. That night Fred spies on Devlin and sees him burying something, which Fred suspects is a body, possibly Mrs. Felson. Fred then talks to Talia, who suddenly vanishes, causing him to think she is a Ghost. Fred imagines Talia as a Ghost in his house, and falls down the stairs reaching for her. There's a knock on the front door and Fred's mother answers it, its Kevin's mother with an invitation to a party. Both Fred and his mother attend the party, where Fred's mother falls for Mr. Devlin (to Fred's horror) and Fred also discovers that Talia is Kevin's sister (also to Fred's horror). The next day Mr. Devlin takes Fred's mother on a date, making Fred extremely uneasy.
Fred then enlists the help of Bertha to lend a hand in getting proof that Devlin is a vampire. Incognito, they spy on Devlin and Fred's mother during their date, which Fred and Bertha nearly bungle. Later that night, Fred attempts to spy on Devlin more, but he falls from his window. Suddenly Fred's "dad" pulls him up and brings him to a wrestling arena, where they tag team against Mr. Devlin and Kevin. Fred's dad beats up Mr. Devlin and Fred eventually pins Kevin. At this point, Fred wakes up, suggesting it was all a dream.
The next day Fred is horrified to discover Mr. Devlin running a blood drive at school. He's even more disturbed to discover Bertha taking personal music lessons from Devlin. Fred runs around gathering items to use as weapons against vampires, including a street sign with a cross on it and a bucket of garlic sauce he gets from a Chinese food restaurant. He plans to take it all to the piano recital the next day, where Mr. Devlin will be performing.
Fred fills up squirt guns with the garlic sauce and arms himself with various other tools he's gathered up for the big vampire eradication. He then goes on a shooting spree at the recital, soaking everyone as he enters, including Talia. But to Fred's horror, Mr. Devlin invites him into his house for dinner after the fiasco, so that they can bury the hatchet. Fred sets up a live video streaming from his telephone so he can prove that Devlin is a vampire, and enters Devlin's house., Fred discovers a secret butchers' room behind a wall filled with meat and bones. As Fred investigates, Devlin creeps in with a long knife and a tall head-dress, scaring Fred; Fred then drops his telephone into a pot of boiling liquid. The video freezes on Devlin, and the frozen image of Devlin in his headdress causes everyone watching the video to think that he is a vampire. But after Devlin explains every weird hobby he has, Fred starts to relate to him, and he comes to realize Devlin is not a vampire, just a very eccentric and interesting guy.
At school he realizes that everyone has seen his video, which makes everyone believe that Devlin is a vampire. He runs to Devlin's house to apologize but Devlin is too depressed to answer. When Fred sees Mr. Devlin get fired, and put up a sign for his house, saying that he is moving, he feels guilty and tries to fix it all by making them think he is the vampire. Bertha and Talia both help, as Talia reveals how much she dislikes her brother. Kevin and his friends go up to Devlin's house because they think he has Talia. Devlin tells them that vampires are not real, but Bertha comes out and says, "Vampires are real, but it's not Devlin. It's him!" Then, Fred walks out of the garage carrying Talia, threatening to turn her into a vampire too. Bertha makes Kevin stab Fred, and he gets sprayed with fake blood. Devlin sees Fred and accepts his apology, revealing that he quit his job and sold his house of his own choice, but still sees Fred as his one true friend. In the end, as Fred's mother and Devlin go out for dinner and go out the door, Fred looks at the mirror in his house and sees that Mr. Devlin has no reflection, revealing that he was a vampire after all, and Fred screams in terror as the film ends.