The light of the stars on the surface of the blade grew in intensity, releasing a blinding flash that turned the Yehval household white. For an Eldritch, the light element was nothing but a snack.
It filled the Spirit Tail with new strength while also blinding everyone nearby. The mercenaries stumbled and died on Endless Night without even noticing while those who kept their distance to cast spells missed their targets and culled their own allies.
The darkness sealing array blocked most of Endless Night's abilities, but it didn't affect the blade's power core. The Spirit Tail used the Blade Tier spell, Unbreakable Bond, to add the energy of Endless Night to his weak core.
It allowed him to convert the world energy that the Davross absorbed into physical strength and mow the waves of enemies down the moment they stepped inside the house.