User blog comment:Chimadino/Who is this guy?/@comment-33590000-20180101181056

The Oni Mask of Hatred turns the user's skin into invulnerable lava/magma-stone.

The Oni Mask of Vengeance turns the user into a swordsmanship master with two additional arms.

A combination of those masks possibly turns the user's sword into invulnerable lava/magma-stone, as seen on the picture.