The Skeleton Soldier Failed to Defend the Dungeon #1 (Link)

A skeleton soldier, tasked with defending a small dungeon, is unable to prevent his boss, a succubus, from being killed. When he, too, is killed, rather than cessation of existence, he is greeted by a message:

You have met all the conditions.

Assimilation rate decreasing.

97.3% -> 94.8%

He wakes up in a coffin, his level reduced from 36 to 1 (but his stats still the same). He is greeted by a necromancer, Rubia--the very necromancer who first brought him to life 20 years ago. He recalls that she was killed by bandits, and he was gravely injured, and resolves to do better this time.

But he's not able to protect her, and this time he, too, is killed, only to wake once again to the sound of Rubia's voice: "Rise from your grave!"