The intertwined fates caused the Elf Queen and the Queen of Desolation to be bound by life.
If the Queen of Desolation kills the Elf Queen, she would also die along with her.
However, there's a flaw in this covenant: should the Queen of Desolation die, the Elf Queen would perish too.
This is why when the tribulation targets the Queen of Desolation, the Elf Queen desperately tries to save her, for if the Queen of Desolation dies, she would follow suit.
Why doesn't the Elf Queen sign a covenant where the Queen of Desolation can't kill her, and her death wouldn't impact the Elf Queen?
The reason lies in the Elf Queen's coveting of the Queen's potential; she wishes to leverage the latter's strength to ascend to a higher Emperor Realm.
This life-bound covenant has the advantage that if one party improves, the other receives a fifty percent feedback, just like how a Beast Master would receive feedback when their pet beast grows stronger.
Moreover, the opportunity is rare.
