Zongman: The villain demon, start by signing in with the Red Dragon Emperor

Traveling through the dxd world, Luo Xiu became a demon noble.
Although his bloodline is impure and he has some succubus blood, he only has Agumon who has been following him since he was a child.
However, he was named the heir of the Leviathan bloodline and had a beautiful young fiancée.
However, as everyone knows, having a powerful fiancée is equivalent to canceling the engagement.
When Cang Na came to cancel the engagement, Luo Xiu awakened the villain sign-in system. By completing the villain sign-in task, he could get system rewards.
[Ding! The host intercepted the Red Dragon Emperor in advance and received a reward: a perfect fusion of the Red Dragon Emperor's gauntlet! ]
[Ding! The host bulls away Irisviel and Tousaka Aoi, and obtains the power of the Minotaur Minotaur! ]
[Ding! The host has conquered three demon princesses: Seekvaira, Rias, and Sona. Reward: True Demon King rank! ]
[Ding! The host possesses the Queen of the Underworld, Gurefia, and obtains a chance to travel through time! ]
Luo Xiu: This is the rise story of a demon noble?
(Dxd for the main world, through being summoned to the four fate wars, Godkiller, Bloodthirster, Fulilian, Earth Wrong, Problem Child, etc.)