The origins of Zardock are unclear even now, despite his prominence in the recent history of Doromir. He approached Morandor, seeking a mentor, and the old wizard accepted him, wondering if he was indeed the chosen one. Zardock seemed more intelligent than Grendel, and more natural attuned to the essence. The people of Doromir fell immediately for his charm, and Grendels friends accepted him readily, despite Grendels protests. He even proposed to Maree, though she politely declined. Zardocks presence in Doromir aggravated Grendel, who suspected the apprentice was up to no good.
He was proven right when Zardock stole the horn or Terelar, Grendels unicorn, and set off to harness the power of the Unicorns vale. Grendel and his friends vowed to stop him, and they pursued him across Rhutalath. The battle ended in Doromir- Zardock captured the town, kidnapped Maree, and unleashed a demon horde with his new-found power. The demons attacked the Mir Valley, culminating in the battle of Gothmarket, where the forces of Ardadain, with the aid of Mep, Elestan and Grendel (arriving with Magog the giant) defeated them. Zardock was slain by Grendel in the highest chambers of Morandors Tower.
The Order of Dral think that Zardock may already have been an apprentice to the great Kyzak Tor (lord of the Green Eye of Dral). His mission in Doromir was to destroy the life of Grendel, and avert the prophecies of the Golden Age. However, the discovery of the Unicorns made him greedy, and he sought to become more powerful than Kyzak Tor himself. Whatever the truth, Zardock had megalomania bordering on insanity, and seemed to have a genuine hatred of both Grendel and Morandor. Maree became an obsession to him, as she spurned his advances.
Zardock may be gone, but Kyzak Tor is doubtless looking for another apprentice, perhaps even setting his sights on Grendel himself.