- "I apologize for how painful the induction process was. Many of your memories were rooted deep. It took effort to pull them out. Tell me... what is your name?"
- —Declan to "Chronos"[src]
Time Master "Declan" was the alias of a member of the Time Masters. He was in charge of training Time Master hopefuls, such as Rip Hunter, and later opposed his old student's team in their quest to stop Vandal Savage. Declan was in charge of bringing the rogue temporal bounty hunter Chronos back under Time Master control, only for said "control" to backfire when "Chronos" refused to attack his friends and killed Declan instead.
While Miranda Coburn and Rip Hunter were training as Time Masters, Declan commended the former, suggesting the latter could learn something from her. However, he later found them getting intimate, forcing them to stand before a disciplinary tribunal for breaking the Time Masters' code. Although initially giving them an hour, Miranda pleaded a moving case on her own, with Declan letting Rip know that she had accepted full responsibility.
Some years later, after Rip Hunter's team were captured by the Time Masters, Declan oversaw the re-brainwashing of Mick Rory into Chronos. With it seemingly working, he allowed him out of his restraints and had him put on his old armor. They went to the team's holding cells, where Leonard Snart had arrived to break his teammates out, after knocking Zaman Druce. Declan ordered for Chronos to fire Snart, but he instead fired at Declan himself. Barely alive, Mick stood on him and crushed him, fulfilling his promise to Declan.
Declan was a dutiful Time Master, who valued the orderly structure and the code of the group above all else, threatening to punish Rip Hunter and Miranda Coburn for breaking the rules of the organization. His adherence to order was also shown when he was in charge of bringing the rogue bounty hunter Chronos back into the fold, as Declan expressed fascination with Chronos as "the greatest of Time Masters' hunters", promising to make sure he goes back to hunting down temporal criminals and time pirates alike.
Declan had a ruthless side, as seen when he tried to make Mick kill his companions and before that, tried to torture him into submission, bringing "Chronos" back. However, he apologized for how painful the indoctrination process was to Mick, although, the sincerity of his apology was doubtful.
Declan was immoral to the point that brainwashed innocent individuals to become the Time Masters personal temporal bounty hunters, he had no guilt, shame or remorse for these vile acts of his, Declan was an emotionless, calm and level-headed, but only when he was in control of a situation, when Mick fired at Declan instead of friends, revealing that he wasn't under the control of the Time Masters, Declan beg the latter for mercy, this proves that he was nothing more than a coward.
These negative traits of Declan's, were what eventually led to his painful yet deserve/justified death at the hands of Mick Rory.