Void Sigil

A lost and forbidden magical formula that can block the flow of Engram Lines, allowing Void Mist to spread.
By controlling "Void Mist" with Hruga's Horn, the magical formula can be activated, thus completing the placement of the sigils.
When all sigils are set, the magical formula will cause a large-scale spread of "Void Mist," leading to a massive Void Cataclysm disaster.