Mineral warrior

A mineral warrior, or a stony devil as they were also called, was a type of creature that had elemental earth as part of their being.

Creation
A mineral warrior was not born naturally. Rather, it was a creature that had subjected itself to transformation magic to become a mineral warrior. It could not be a construct, elemental, or undead.

Description
They looked like petrified versions of themselves, but this had no effect on their agility.

Personality
As a general rule, a mineral warrior was a creature that had willingly become one. However, some became mineral warriors because they'd been forced into the transformation by a member of an evil race from the Underdark.

Combat
Becoming a mineral warrior provided a lot of benefits for the one who became one. They could burrow through the ground as fast as they could walk. However, they lost all ability to fly naturally.

Their skin became tougher and even when an opponent managed to effectively hit a mineral warrior, it was hard to hurt them unless they used an adamantine weapon.

A mineral warrior gained darkvision.

A mineral warrior gained enhanced physical strength and durability, but all aspects of their mental capacity dropped. It was even possible for the creature to drop to animal intelligence.

The most devastating attack of a mineral warrior was called earth attack. This attack was only usable against creatures who stood on stone or earth. It was a vicious attack that became more accurate as the durability of the mineral warrior increased.

History
By the 14 century DR, the spell mineralize warrior had been developed that changed a willing humanoid into a mineral warrior.