There was a reason why every demon placed immense importance on one's bloodline and its grade.
A demon with a Lesser Bloodline can never become an Archfiend in a natural manner because of the size of their chaos flame.
When one goes through their Coming of Age Rite, they awaken their bloodline and chaos flame.
The first heart rank is called a Flickering Heart because the awakened chaos flame is usually in the form of a flickering flame.
However, the size and density of the flickering flame is usually dependent on the demon's bloodline.
A demon with a Lesser Bloodline awakens a flickering chaos flame that was comparable to the size of a candle wick.
A demon with a Common Bloodline awakens a flickering chaos flame comparable to the size of a thumb-sized flame.
A demon with a Noble Bloodline awakens a flickering chaos flame that was comparable to the size of a palm sized flame.
