|This article is about a/an episode in Battle Fever J.|
The Friend Who Became a Demon (悪魔になった友 Akuma ni Natta Tomo) is the thiry-ninth episode of Battle Fever J.
A sickly doctor friend of Jin becomes an Egos Monster in hopes of gaining eternal life, even at the cost of his humanity.
Jin goes to his yearly physical at Johoku University, and his physician and friend Dr. Sekine seems to be showing the signs of an ulcer. Sarome lures him to a facility called the immortal club, where they reveal he has malignant cancer and 3 months left to live. They then give him the option of joining Egos and having immortality. Egos turns him into a Jekyl/Hyde type of vampire. Fearing for his friend Jin asks Kenya to brew him some African herbal remedy, when they discover the vampire. The proximity to Sekine’s condo makes Jin begin to suspect his friend. Unable to control his transformations, Sekine kills his rival and his supervisor, giving him promotion after promotion. Battle Fever moved to protect his love interest, Noriko and they confirm their suspicions.
- This is the second time a person intentionally becomes an Egos Monster; the first was the psychic Bengal Tiger who became the Psychokinesis Monster in episode 4. However the former was a volunteer recruited by Egos, while Sekine was seduced by his sickness into becoming the Hyde Monster.
- Doctor Sekine (and the Hyde counterpart) is portrayed by Shinji Todo; he previously portrayed Spider-Man in the tokusatsu that bridged the gap between J.A.K.Q. and BFJ and will next appear in Sentai as General Hedrer in next season's Denziman