As he circulated Essence through his whole body, black reeking impurities began to ooze out of his body. The slimy mass trickled down his body where it formed a stinky puddle.
Blazing flames engulfed Dilan all of a sudden, burning the impurities down to its last atom. Dilan's skin was burned as well, but he healed quickly enough to survive the danger of the burning flames.
He grit his teeth in pain but ignored the problems of a mortal and accepted the pain while continuing to circulate the Essence from the surroundings inside him.
The City of Trials was rich in Essence and Dilan made use of the great opportunity as he learned the Perfect Essence Cultivation technique from its creator personally.
He was learning fast, but the technique was everything but easy. After a thousand years had passed inside the City of Trials, Dilan was still only at the Fourth Stage of the Essence Cultivation Technique. The higher the stage the higher the difficulty to practice the technique.