Neo-obsidian

In a distant, possibly alternate future, in a faraway corner of the Worldplane, a civilization has developed a technique to enhance obsidian's durability to the point of being literally unbreakable.

Unlike regular obsidian, which may possibly be damaged if a cosmic amount of force rarely seen on the average world is applied to it, this highly refined version is impossible to physically alter against its will by any finite amount of physical force.

The metal seems to have a certain autonomous consciousness or intelligence, although it is not clear whether it can be considered to be alive, as it lacks even trace amounts of ether. In the case of a living being like Neo Surtur, whose body is made out of the material, this entity appears to have fully merged with his prior mind (which in his case already happened to contain multiple beings) as opposed to existing alongside and independently of it.

This metallic version of the material is much lighter in tone than the original, being dark grey with a much shinier hue.