Crystilak

Crystilak is a Popopo of pure obsidian, and the sister of Obsidias, as well as a member of The Mineral Sisters.

History
Just like The Ore Brothers, Obsidias and Crystilak were just everyday normal Popopos dong everyday normal things. However, one day, they found something that would alter their mindset and appearance forever...

On that day, Obsidias and Crystilak wanted to play hide-and-seek. Crystilak started counting, and Obisidias started to hide. When she was finding a place to hide, she stumbled across a ice/crystal mountain. Thinking that would suffice as a decent hiding spot, she entered the mountain via a tunnel.

Crystilak quickly saw where Obsidias was going after counting, so she quikcly headed after her. Upon arriving inside the mountain tunnel, she saw Obsidias, completely still, gawking at nothing more than a glowing crystal and a glowing piece of obsidian. Curiosity eating them inside, the two stopped playing hide-and-seek and decided to pick up the minerals for further inspection, so Obsidias picked up the obsidian and Crystilak picked up the crystal.

However, upon touching their respective minerals, an aura from each of the minerals overwhelmed the sisters, slowly turning them to what they are now. Obviously, they were terrified upon noticing their transformation, however, as time progressed, they had realized they can do powers of their respective mineral, much like the Ore Brothers. Thanks to the realization, the sisters thought of a new mindset; to place fear into people's hearts and show them "who's boss".

Weeks later, the Mineral Sisters stumbled across The Epsilon Quartet, and decided to fight them. In the end, the Quartet won, and the sisters fled. Days after, the Mineral Sisters returned to rematch the Quartet, only this time with the aid of the Ore Brothers. Now it was an even fight; 4 vs. 4, but in the end, the Quartet still remained victorious, and the opponents fled yet again.

To this day, the Ore Brothers and the Mineral Sisters still haven't defeated the Quartet, and they will continue to persist to fight them until they win.

Personality
Much like how Goldraxon is different from Ironos in a sense that Goldraxon is more calm and leading than his brother, Crystilak is like Goldraxon. She acts more of a leader and caretaker, and due to this, she acts like an older sister of Obsidias, even though they are the same age.

Obsidian also has a tendency to vehement fights and tempestuous quarrels with her sister, though they do fight occasionally, they still love each other as sisters.

Trivia

 * Crystilak has a love interest with Goldraxon, one of The Ore Brothers, who also loves her the same way.