Miltiades, although not specifically referred to as a death knight, was a skeletal undead paladin. Miltiades grew up in the city of Turell. He was its steward and champion. Due to his service, he was given the Holy Shield of Tyr, a magical war helm, and a runic sword of Tyr. For fifty years, he faithfully guarded the city, until the battlemage Zarl attacked. Turell was besieged for a year, during which he personally slew many of Zarl's greatest warriors. Zarl never challenged Miltiades, so Miltiades sneaked into Zarl's camp one night and murdered him dishonorably. Miltiades was then slain by all of Zarl's men, and Turell was sacked and destroyed without its protector. Tyr refused to allow Miltiades to die and rest in honor, leaving his spirit to wander.
A thousand years later, Tyr tasked the half-dead Miltiades with finding the lost city of Phlan, which had been captured by Bane's minions, the red wizard Marcus and the pit fiend Tanetal. Upon his resurrection, Miltiades met Ren o' the Blade, Evaine and her familiar Gamaliel, and the druid cousins Androlson and Talenthia. Shortly after, Miltiades slew the ghost of Zarl, but during the battle, the Holy Shield of Tyr was destroyed. Miltiades and his companions rescued Phlan, and Miltiades entered a peaceful slumber.
A few years later, Tyr once again raised Miltiades to help the son of Shal and Tarl find and recover the Hammer of Tyr. At the end of the successful mission, a paladin of Tyr named Trooper gave his soul to his patron deity to restore Miltiades to life. Miltiades and Evaine later started a relationship, but their prior duties put it on hold.
Miltiades returned in The Double Diamond Triangle Saga, leading a small group of adventurers sent from Waterdeep to the Utter East.