Where did the Moonlight Sword come from?
In King’s Field (1994) the Moonlight Sword is a secret with a procedure: carry the Dragon Sword to the fairy Milia on the fifth floor of the Royal Cemetery, and she awakens it into the strongest weapon in the game. It already fires its signature attack, a wave of light released by pressing the magic button in time with a swing, with no spell equipped. In this first form it is a one-handed sword, about 120 centimeters, blue-green and glowing. The greatsword it later becomes was still ten years of sequels away.
The lore the series built around it is a creation myth. The god Vallad split into two dragons: Seath the White Dragon and Guyra the Black Dragon. Guyra forged the Moonlight Sword to gather warriors for his own revival, telling them the blade held half his spirit; Seath answered with a dark counterpart, the Dark Slayer. King’s Field II is the sword’s theft and recovery, though the blade Aleph actually fights with is the Dark Slayer, and he regains the Moonlight Sword only at the ending. In III the sword is shattered and restored, and in both III and IV the ending itself turns on whether you hold it.