Arcanium Metal.
An extremely powerful, mana-infused metal that is often used for a variety of things. Arcane weapons and armor, formation plates, doors leading to treasuries, and soundproofing. Arcanium had the tendency to draw mana into itself, but it also rejected every other energy and force that came its way.
'Vibrations count as well.'
Which is why Alaric used it for soundproofing the dungeon he kept Cini in. Simply put, he wanted to keep Cini a secret in the future. Even those people that had fed her in the past were told that Cini died in the war against the Fen family.
But, another benefit of Arcanium metal, which was rarely used, was that it wouldn't corrode.
"If you slimes don't know what that means... then I'll explain simply."
Alaric looked at the colossal Cini, and his allies Pamela and Sonic, who had already arrived at his side.
"Cini is too weak to pull this off."