Dark Wizard (1) Yomigaerishi Tami no Madoushi

is the first volume of the Dark Wizard light novel series, written by Terada Kenshi and Illustrated by Takahiro Toyomasu. It was released under the Dengeki Bunko Imprint in June 1993.

Synopsis
Veronese, a mage who has been immortalized to watch over the sealed  by Ahriman, the dark god, and has carved 300 years in the shrine. Now, the man was trying to summon monsters to this land, a green continent, and gradually repaint the world into "darkness" in order to set the stage for reviving Ahriman. Meanwhile, Ahura Mazda, the goddess of light, was in the hands of King Wen-li VIII, the key to unlocking the sealed Jewel of Light. And the monsters aiming for it had already invaded the castle. However, due to fate, the Holy King was defeated by a woman, the Dark Elf, and even her wand of light was robbed by that woman. His son, Wen-li IX, sets out on a journey to chase the Dark Elves to avenge his father's death.

(source: Amazon JP - Translated)