"From what I know, the differences between a low, intermediate, high, and peak grade hell stone is the crystal itself and most importantly, the flame."
Simon turned the hell stone in his hand and observed it with a curious gaze.
It was slightly warm, and even as he held the hell stone, the passive stage of Devour was absorbing the demonic energy in it.
"A low grade hell stone has an uneven shape with chipped edges. It’s rough and also cloudy, and the flame in it is a small, flickering dull red flame."
He paused, then his eyes flickered slightly.
"An intermediate grade hell stone is clearer and more symmetrical. It has smooth edges, and the flame is stable and has a darker and brighter colour."
"It moves naturally and emits no smoke unlike a low grade hell stone."
He paused, then he began moving the hell stone in between his fingers.
"And for a high grade hell stone, that’s where things begin to change."
"It has nigh-perfect transparency. It’s sharp and cut like a gem. The flame is larger and denser, filling much of the crystal. And the flame can have two different colours."
"It can either be deep blood-red or it can be black."
Ting
He flicked the hell stone to the ceiling, and without looking at it, he kept on talking.
"And for a peak grade hell stone...many have never seen that grade of hell stone. Apparently, it’s meant for Demon Kings and maybe some talented Demon Lords. However..."
Grab
He swiped his hand to the side and he grabbed the falling hell stone.
"... The book I read mentioned its appearance, and it heaped all sorts of praise on peak grade hell stones."
He paused, his gaze fixed on the low grade hell stone laying flat on his palm. Its flame was flickering and was nearly dying, and Simon’s sky-blue eyes reflected this sight.
"A peak grade hell stone is nearly a perfect crystal, and it’s almost unreal. The flame is... not quite a flame anymore."
"The flame is now a floating core of darkness with burning deep blood edges."
"From what I know, Demon Kings can battle themselves for a single peak grade hell stone."
The moment he said these words, he clenched his fist, and when he opened them, the hell stone crumbled to ash.
With the help of Devour, he had finished absorbing the demonic energy in the hell stone.
"Hmm."
Simon hummed softly as he clenched his fist and unclenched it.
"So it wasn’t able to increase my demonic energy by a single percentage."
He clenched his fist again, then he brought out another hell stone.
"Let’s see how many low grade hell stones I need to increase the refinement of my chaos heart from 11% to 12%."
He looked at the hell stone, and without hesitation, he actively used Devour on it instead of wasting time absorbing the demonic energy in the hell stones.
In approximately ten seconds, the hell stone crumbled to ash but there was still no increase in the refinement of his heart.
However, Simon was calm and he indifferently brought out another hell stone.
He devoured it but there was still no change.
He kept on doing this repeatedly until he devoured the tenth hell stone.
"Hmm."
Simon looked down and watched as the last hell stone turned to ash.
"It took ten hell stones for me to advance by a single percentage, and the higher the percentage, the more demonic energy I’ll need."
He furrowed his brows slightly.
"The difference between renting a low grade cultivation room and using ten low grade hell stone is little."
"But low grade hell stones are still better in my opinion."
He released a soft sigh, then he stood.
"I might need to buy an intermediate hell stone to see the difference between that and a low grade hell stone."
Having nothing else to do, he walked out of the room, then the tower.
He decided not to waste his hell stones since his goal is not to raise his heart rank too quickly.
Besides, he could use the hell stones for something else.
"Now, what should I do?"
As he stood outside the cultivation tower, he furrowed his brows slightly.
He had a lot of free time at the moment, and since he was not planning on increasing his heart rank, he wanted to use it to do something else.
’Should I go to the library? Practice chaos runes? Or should I look for an instructor to personally teach me in the art of fighting without weapons?’
’Which would be more important for me?’
He looked down with a thoughtful expression, then he started walking to the front with an absent-minded gaze.
’Practicing chaos runes should be more important for me, but I should look for an instructor first.’
’Books on chaos runes are readily available, but I might struggle finding an instructor. Even if I do, I need to know the schedule of our training so that I can better plan my time.’
His eyes flashed with a satisfied light, then he opened his right hand and looked at it.
’Let me go through the Grave Mark and look for those I can hire.’
Just as he was about to send his intent into his Grave Mark, he looked up, then he looked down, then he looked up again with a frown.
His steps slowed down till he came to a complete stop.
In front of him was Sunless who had her arms folded and her right foot repeatedly tapping the ground.
He paused a few meters in front of her, and though he knew why she was in front of him, he decided to be shameless.
"What is it?"
Sunless chuckled dangerously behind her mask.
"Are you trying to renege on our agreement?"
Simon’s lips twitched as he recalled the excessive food she ordered previously.
"I’ve been busy." He said calmly.
Sunless scoffed. "Well, I’m hungry. Get me food... Lots of it."
"..." Simon’s left eye could not help but twitch.