Nyzerin

Nyzerin was the previous Demonlord, having crowned himself with the title, he subjugated all who opposed him with his sheer strength and magical aptitude, enforcing peace between the warring factions. Nyzerin ruled all Demonkind for five centuries until he was killed by Nen about a 100 years ago.

The Hatespines are extremely devoted to him, going so far as to deify him, and consider Nen "the Betrayer" for her actions against him. Many other groups that pledged allegiance to him also worshipped him to different degrees.