- "I do some carving, now and then."
- ―Sebastian Derik
Sebastian Derik was a S.H.I.E.L.D. agent working as an assassin until he became the test subject of Project T.A.H.I.T.I. After the serum's harmful effects began to take hold, his memories were erased and he was given a new identity. Unlike his former colleagues, he later remembered who he really was, suffering from the side effects of the GH.325 serum.
Agent of S.H.I.E.L.D.
- "How long you gonna keep me with these lunatics, Coulson?"
- ―Sebastian Derik to Phil Coulson
Derik, along with five other agents, was handpicked by Agent Phil Coulson as a test subject for the T.A.H.I.T.I. Project. At first he had a successful recovery; however, Derik eventually began cutting the Words of Creation into his flesh. Despite his claims that he was fine, Coulson had his memory erased and gave him a new identity. Derik continued to write the blueprints even after losing his memories, carving it on a wall  and then eventually tattooing it on his body.  Due to the pain, Derik eventually remembered who he was and who else was part of the T.A.H.I.T.I. Project.
Visiting Tattoo Parlors
- "The pain helps me remember."
- ―Sebastian Derik
Sebastian Derik visited a tattoo parlor, and paid an artist who had previously worked on him. The artist suggested to him that he should wait, for the fresh tattoos had not yet healed, but Derik insisted. As Derik removed his shirt, the artist told him that the procedure would be painful. Derik, covered with the Words of Creation, told him that the pain helped him to remember.
Killing the Patients
- "The lunatics are running the asylum."
- ―Sebastian Derik
Derik began to search for Phil Coulson, but all of his sources told him that he was dead. In Miami, Florida, Derik found Lewis Seaver. Seaver was killed and Derik burned down the church where he worked. The only thing that remained unscathed was a painting with the Words of Creation inscribed on its back. In Rhinebeck, New York, Derik went to a bar and met Janice Robbins and the two went to her apartment. Derik revealed that they did in fact know each other and he would help her remember. He removed his shirt, showing the Words of Creation tattooed on his body. Robbins asked Derik how he knew about the symbols; Derik began cutting her in an attempt to help her remember the past, eventually killing her.
Derik killed two other former T.A.H.I.T.I. patients, because none of them could survive the pain of having the symbols carved into them. He would ask them if they knew about the symbols; if they did, Derik wanted an explanation as to why they were writing them. If they could not give one, Derik hoped that the pain of carving the symbols into their bodies would help them to recall. Eventually, Derik found Hank Thompson, another former T.A.H.I.T.I. Patient. Thompson told Derik that he knew nothing about the symbols; in reality, Thompson was making the symbols three-dimensionally in the model train tracks he and his son erected in the garage.
Derik was in Thompson's home when Phil Coulson knocked on the door and began asking about the symbols. When Coulson realized that he was there, Derik knocked him unconscious. Knowing that Coulson was there to rescue Thompson, Derik restrained them both and also held Thompson's wife and son hostage. Derik removed his shirt, revealing the Words of Creation and explained his reasons for tracking down and murdering the other T.A.H.I.T.I. patients. Derik began to cut Coulson's skin, telling him that the pain of the torture would help him to remember and would allow them to finally learn what the symbols mean.
Thompson managed to escape and free Coulson from his noose. After a brief fight between Derik and Coulson, Derik spotted the last piece of the puzzle: a toy train track system that Thompson had built which created a 3D model of the symbols. At the revelation, Derik calmed, knowing the answer to the symbols: they were blueprints to a city. Derik was taken into custody by authorities for his murder spree and crimes he had committed before his quest began.
- Expert Assassin: Derik was trained by S.H.I.E.L.D. and became an expert assassin, skilled in guile and killing. Derik knew enough about human physiology to cut a person selectively without having that person die from the cuts; they would die from shock and trauma, but not the actual incisions. He was viewed as a valued asset by S.H.I.E.L.D., enough for Phil Coulson to recruit him for Project T.A.H.I.T.I. when it was discovered that he was dying.
- Phil Coulson - Former Project T.A.H.I.T.I. Supervisor
- Alphonso Mackenzie
- Project T.A.H.I.T.I.
- Katie Thompson - Hostage
- Hank Thompson's Son - Hostage
- The T.A.H.I.T.I. project's primary negative effect on his mind was the inability to realize he was ruining the lives of former S.H.I.E.L.D. agents in his mad quest for answers.