Summoning Frenzy: Skeleton Evolution

Hundreds of years ago, countless rifts in space and time appeared on Earth. Dragons, monsters, demons, insectoid races, undead, and elemental races invaded, and humanity went to war against them all. Thus began the Dark Age.

The young Bai Gu woke up in the post-apocalyptic world hundreds of years in the future and became a summoner. From the start, he summoned the most useless little skeleton. But he had a System that could evolve and strengthen his summons.

From a little skeleton, they could evolve into skeleton warriors, skeleton archers, skeleton mages, bone knights, ghostbone assassins, liches, skeleton kings, poison dagger throwers, bone knights, and bone giants.