Stargazer used the powers of the Yggdrasill wood to mix the rune of its enchantments with those conjured by her mind to conjure another Frozen Storm in less than half the time that a regular Awakened would need to weave such a powerful spell.
The Davross blade was meant as an amplifier and as a last mean resort. The true power of the cursed glaive came from the mystical wood and the Evil Eyes of an unfallen Balor.
Stargazer's maker had been a powerful mage who had used the unique abilities of the World Tree to shorten the cast time of any spell and the Evil Eyes to achieve the next best thing to Domination along with an endless supply of power for the wielder of his masterpiece.
Alas, the hybrid had already witnessed a Frozen Storm and even though they couldn't afford to Dominate it again due to the focus needed to keep Windfell under pressure, they still had arrows to their quiver.