Doctor Evan Declan was a geneticist studying the Inhumans while being secretly funded by Maximus to find the genetic key to Terrigenesis. After meeting Black Bolt, he was forced to work with Auran to lure the King of the Inhumans into a trap. Declan was released by the Inhuman Royal Family and taken to the Moon with them, where they agreed to hand him over to Maximus. Declan was ready to help Maximus undergo a second Terrigenesis, but he was brutally murdered by a recently revived Gorgon.
Evan Declan was a geneticist working in his own company, Declan Research. He undertook research about the Inhumans and more specifically about what was responsible of their transformation during the process known as Terrigenesis. Unbeknownst to him, however, his research were funded by Maximus, Prince of Attilan, who intended to undergo through a second Terrigenesis after the first one turned him into a simple Human.
Declan found many Inhumans he studied and collected data about, keeping record of their powers.
Meeting Black Bolt
- "I'm both in awe of you and slightly terrified. Extremely terrified of you."
- ―Evan Declan to Black Bolt
While exiting the Declan Research Facility in Santa Barbara, California, Declaan was showed by his assistant a footage of Black Bolt throwing a car in the air through the simple use of his voice. Suspecting that Black Bolt might be an Inhuman, Declan decided to fly to Oahu. Learning that Black Bolt was detained in Oahu County Correctional Facility, Declan called Sammy, who was also an Inhuman imprisoned there, and offered him an opportunity to escape from jail if he agreed to help Declan find Black Bolt. Black Bolt and Sammy successfully escaped from prison. They were picked up by Declan, who had flown a helicopter to the place in order to take them to his lab.
Declan introduced himself to Black Bolt and Sammy and expressed his intent to study their DNA, though he insisted that they were free to refuse and to leave anytime they wanted. As Black Bolt noticed Declan's wedding ring, Declan suggested that Medusa might be among the Inhumans he had welcomed in his lab.
Once in the lab, Declan studied Black Bolt's DNA and found out that it was very different from the other Inhumans he knew about. He also reiterated his promise of helping Black Bolt find his wife before going outside and calling his benefactor Maximus to explain his discovery, unaware that Maximus was Black Bolt's brother and that he wanted his brother dead. However, Declan refused to kill Declan on the sole reason that his power was dangerous as Declan needed him alive to study his DNA and discover the genetic mechanisms of Terrigenesis.
Working for Auran
- "Your telomeres are growing shorter."
"Meaning you may not be able to regenerate yourself forever. One day, you'll die and that's it."
- ―Evan Declan and Auran
Declan reclaimed the bodies of Auran and Sakas who were killed during the Ambush at Declan Research Facility Lab. He performed an autopsy on Sakas and isolated his venom glands, which released corrosive chemicals and nearly hurt Declan. Declan asked his assistant to perform some DNA tests and to compare the results to Black Bolt's DNA.
While they were reviewing the results of the tests, which showed some kind of degradation in Auran's DNA, Auran was revived and healed by her powers much to Declan's astonishment. Auran began choking Declan, demanding to know where Black Bolt was. Declan's assistant chose the moment to attack Auran with a scalpel, but she easily avoided the strike and murdered him.
Upon learning that Black Bolt was in debt with Declan for having taken him out of jail, Auran decided to use him as a bait along with Sammy, who had been captured by Mordis and Flora, to lure Black Bolt into a trap. Declan was strapped to a chair and kept under surveillance of Auran's team. While awaiting for the Inhuman Royal Family to show up, Declan warned Auran that her powers could wither and possibly fail her. However, Auran refused to believe him.
Karnak and Gorgon eventually infiltrated into the lab. Auran held Declan at gunpoint to keep them from doing damage, but Gorgon violently attacked her, enabling Karnak to release Declan. Upon learning who Maximus really was, Declan revealed to Karnak that Maximus had funded his research. However, the lab was destroyed when Mordis decided to commit suicide rather than being locked away again. After the battle who saw Gorgon's death, Declan was taken by the Inhuman Royal Family.
Traded to Maximus
Declan was taken to the Royal Bunker by the Inhuman Royal Family, who explained that he was on the Moon, much to Declan's amazement. He was then asked by Karnak to explain his research and why Maximus had hired him, making Karnak understand that Maximus intended to undergo a second Terrigenesis.
Declan later accompanied the Inhuman Royal Family for parley. They agreed to let Declan go with Maximus. As a result, Declan was taken into the Attilan palace. He was visited by Maximus, who expressed his desire to see Declan's work. Maximus explained to Declan that he wanted to choose powers among the list of Inhumans Declan had acquired, and although Declan expressed his doubts about the safety of the process, Maximus was keen on performing it as soon as possible.
As Auran reported multiple malfunctions across the city of Attilan, Maximus ordered Declan to come with him to the Terrigenesis Chambers so he could see what Terrigen Crystals were. There, they found Gorgon's body in one of the Chambers. As the malfunctions went more severe, Declan was told to remain alone in the room while Maximus and his men attempted to fix the situation.
- "I can help you. Just... Please just... Just stay back. I don't want to hurt you, but I will! I will hurt you! Just stay back!"
- ―Evan Declan to Gorgon
While Declan was examining a Terrigen Crystal, he saw Gorgon being revived and slowly approaching him with an angry look. Although Declan tried to calm Gorgon down, he was overpowered by a disoriented Gorgon who violently threw him in a Terrigenesis chamber, instantly killing Declan. Declan's body was later found by Auran and Maximus.
Despite being funded by Maximus who intended to overthrow and even kill his family, Declan was not motivated by evil or malevolent motives. Instead, his actions were only guided by his will to discover what were the genetic mechanisms of Terrigenesis. He was willing to help Maximus undergo a second Terrigenesis because he did not know what it really implied for the whole city of Attilan.
- Expert Scientist: Declan was a brilliant geneticist who studied Inhuman genetics for a long time, creating his own research structure Declan Research to do so. During his research, he gathered information about many Inhumans in order to find out what made Terrigenesis possible in their DNA. Declan knew enough about Inhuman abilities to infer that Auran's regenerative healing factor would weaken over time and could even one day fail her.
- Com-Link: Along with Maximus' funds, Declan was provided with a Com-Link he used to contact his secret benefactor, unaware that his correspondent was actually on the Moon.