Protosteel was the hardest substance known to exist. It was created by the artisans of Artakha and used to craft the armor of the Brotherhood of Makuta. It required tremendous force to pierce or crack; it was not unbreakable or invulnerable.1
Protosteel was the hardest substance in the known universe.2
Notes
Protosteel was stronger than Makuta armor and solid protodermis.3
Protosteel was the only substance tougher than Brotherhood of Makuta armor.4
Protosteel was the only known substance harder than Brotherhood of Makuta armor.5
Protosteel was the only weakness of the Brotherhood of Makuta's armor.6
Other Information
- Protosteel was to solid protodermis as adamantium was to iron in X-Men.7