A mysterious swordsman who possesses eternal life as well as the ability to assume human form, Deker is regarded by the rest of Xandred's crew as a loner, and prefers to go about business his way. With his trusty sword Uramasa in hand, he seeks the perfect opponent to satiate his thirst for battle, feeling that his immortality is wasted otherwise.
He first made himself known to them when he appeared to save Dayu from defeat. He later approached the Rangers in his human guise and observed the battle between Jayden and Kevin himself, dismissing their questions about his identity and keenly noting Jayden's actions, ultimately realizing that he had at long last found the warrior he sought in the Red Samurai Ranger.
Finally purged of his Nighlok side and fully human, Deker discovered a black power disc that infused him with the Samurai Symbol power of Night and awoke the Scorpion Zord. Deker became the Black Samurai Ranger. He aids the Rangers, but the Samurai Rangers (especially Jayden) are wary of the new Black Ranger
When the Samurai Rangers return in the series Power Rangers Oceanforce, a villain named Diephin ends up erasing his memory and turning him into a full Nighlok, making the rangers need to destroy him to make him a human again. When he is destroyed, he is given the form of Black Oceanforce Ranger.