He's the youngest of the three brothers.
Moraciel and his two brothers got abducted at young age by humans who enslaved them and abused them.
Harvesting their silk and gas (which can be used as aphrodisiac or even as narcotic) and even using them as sex toys for wealthy customers.
One day the brothers managed to flee their prison and they found shelter in the catacombs of the city Kaijati, which is overall surrounded by a vast desert but near an oasis.
Hiding in those catacombs, they were planning their revenge against the humans who misstreated them so badly.