Originally an Etrurian gladiator, Dieck attracted the attention of the nobles, Pent and Louise, who offered him a job as Klein's guardian. Dieck had saved Klein when he was a boy from a charging lion, whose claws dug into his body, leaving deep scars. Pent and Louise did not mind that he fought alongside the gladiators in arenas and charged Dieck with the protection of their son. Dieck left their service some time later when nobles pressured House Reglay with the fact that Dieck should not be involved with nobility, being of common blood. Klein, however, never forgot his former playmate and protector.
Before he was hired by Eliwood to serve Roy's army, Dieck and his group of mercenaries had been recruited by a certain lord to fight against his enemies. That lord, in an effort to buy time to escape, abandoned the mercenaries. Many were slaughtered, leaving Dieck the only survivor, and his foes captured and tortured him. He later hires two young axefighters named Wade and Lot, as well as an Ilian Pegasus knight named Shanna.