Gele

A former sage in her previous human days. Her wisdom caught the jealousy of many others, and she was persecuted because of that.

The previous Demon King Nighcisa came upon her battered and tortured body by chance and chose her as the next Demon King, thus starting the GL era. Warped by her bitter past experiences, Gele became the cruelest Demon King known to mankind.

Unlike the previous Demon King, Gele did not actively kill a huge number of humans. Rather, she chose to place them under slavery and the harshest living conditions. Doing otherwise, would only empower the chosen Hero to a level of strength that would be a threat to her.

A Demon King has a fixed life span of roughly 1000 years, after which he must chose a successor to pass on the power. Failing to do so will cause his own body to be swallowed by the curse of the Demon King's blood.

However, Gele was taught a way to bend the rules by one of the Gods. By transferring most of her Demon King's blood to another person, she could live on as the Demon King even after 1000 years has passed.

The downside to this is a her strength would be reduced to 5% of her original power. Gele chose her most trusted aide, Gi to receive most of her blood. Something that would cause her fall as Demon King later on.