Calvin is a fairly tall man with a dark brown skin-tone, brown eyes and no hair. However, after being experimented on by Black Manta he now possesses gills and webbed hands and feet. He wears a simple, skintight purple Atlantean garment. Around his waist is a lighter colored stripe like a belt. There is a stripe in the same color around the end of his sleeves, and over his shins as well.
Durham was originally from San Diego. The lack of opportunities there drove him to become one of Black Manta's henchmen. He was genetically engineered to become a water-breather to infiltrate and destroy Atlantis from the inside, but he forsook his mission when he met Sha'lain'a. They married, and he raised Kaldur'ahm as his son in the city of Shayeris.
Calvin initially struggled to adjusting to life underwater and was often away from home during Kaldur's early years. He struggled to find regular work, and fell in with Krush's criminal gang for a time, but eventually found an honest path.
At the first day of proper talks, Calvin started to speak on the lack of opportunity in Shayeris. When he mentioned Black Manta, Nanaue Sha'ark gleefully reminded everyone of his history. Kaldur insisted Manta was irrelevant and that Calvin was his father in every way that mattered. Lord Ronal remarked that Durham was only there because he was Kadlur'ahm's father, but apologized after being chastened by Lori Lemaris. When Calvin finally got to finish his point on the economic inequality between the city states, he found easy agreement from the other representatives. Before Orin could fully respond, Ocean-Master attacked the conference. Calvin helped an injured Vulko while the battle went on, and was as surprised as everyone else when a powerful stranger appeared to save the day.
Calvin and Sha'lain'a received a call from Kaldur, as they requested through Delphis. They told him they were worried that he was taking on too much. Kaldur objected, saying he only did what was necessary. His parents reminded him that he had been overly responsible since his childhood, and told him that he needed to take some time for himself. Kaldur insisted on continuing his search for Ocean-Master, then was called away and had to end the call.
As public unrest grew, Calvin was one of a number of representatives to call in to a Conference of Delegates at the Xebelian palace. It quickly became clear that they intended to elect a new High King, just as Arion and Chian arrived at the palace. Like most of the delegates, Calvin voted in favor of Arion taking the throne.
Calvin and Sha'lain'a watched Arion's coronation speech, and saw him die shortly after donning Arion's crown. Calvin was part of the unanimous vote to make Mera the new High King. By the time Mera gave her speech, Calvin and Sha'lain'a had left their home to join those celebrating outside.
Powers and abilities
Atlantean attributes:[nb 1] Atlanteans, although human, have through scientific and sorcerous means developed several abilities which allow them to live comfortably under the sea:
Underwater breathing: As a result of his experimentation, Calvin has gained the Atlanteans abilities of surviving the aquatic atmosphere under the sea. Some accomplish this without the presence of visible gills.
Temperature resilience: Resistant to low temperatures and the effects of freezing, although notably hindered by high temperatures.