Your body is hardened crystal, and you can walk through acid, and fire without flinching, and it will make little difference. Not even the strongest man in the world can escape unscathed, as you can hit back without hitting back. 

Born from the mountain's darkness, you can see in complete darkness

You can move freely among the earth, as it can stand stronger for you

As you are born from the mountain, you can live for hundreds of years, almost making it to a half of a millennia. They mature slower than humans, as Brisums learn to walk at the age of 5. They gain their normal sight at the age of 10, and they call it the day Malyr blesses them. They then reach maturity at age 30-35, andcan live to be 500 years old, though some can live to be 750-1000 years. 

Brisums are usually around 6-7 feet tall, though the tallest is 8 foot, and the shortest is 5 foot. Your size is medium.

As you are made of crystals, you weigh more than a fully grown goliath, weighing over 300 pounds on average.

If you came from the mountains, your body is hardened, and your mind as well. If you lived in the cities, you learned to talk your way out of fights, but your crystalline skin has saved you from a stray knife.