A brilliant veteran tactician who served within the forces of King Randor following the disappearance of the Council of Elders. Dekker served as an elite warrior for the forces of good on Eternia and knew the Captain Randor at one point as "Randy". He was instrumental in training the young Man-At-Arms in the arts of war and taught him everything he knew about strategy as well as warfare. Furthermore, he emphasized the point that one never stopped learning across their life and instead developed new skills with the passage of time. At an unknown point, he and Duncan were at the Isle of Blakely where they were ambushed by a group of bandits. There, they developed a strategy of goading the enemy into unintentionally releasing them whereupon they defeated their captors.
At some point, Dekker returned from his service as a warrior and lived on the Orkas Island where he adopted a life of solitude and used to enjoy fishing. During this time, Man-At-Arms was scheduled to meet him but a pair of beings of Clawful's race overheard his association with Duncan thus leading to Dekker being captured in order to be used as bait. This was with the intention of trading Man-At-Arms to Skeletor in order to be rewarded.
Dekker is a man with the strength of a man his age with heavy physical exercise. Dekker is a great melee fighter. In his action figure in Masters of Universe Classics, Dekker is armed with a metal club.