Deke was conceived by "other John", an identical duplicate of John Crichton. The crew of Moya was separated, and Aeryn and other John were living aboard Talyn, Moya's child. Other John died soon, leaving Aeryn heartbroken and confused. Moya's John, however, had accepted Deke as his own when he found out.
During the attack of Eidelon, John and pregnant Aeryn were crystallized. Rygel managed to restore them by eating all of their pieces, but fetus ended up inside him instead of Aeryn, and was transferred back only after capture by Scarrans.
Deke was born in the midst of a war between Peacekeepers and Scarrans and named after D'argo.
Some time after the end of the war an assassin named Roiin tried to kill him. He failed, but continues to chase after Moya.