My First Spell Was Skeleton Summon, But It Cast 100 Million Times And Broke The World!

What the story is about

In a class-based world threatened by dungeons and invading demons, necromancer Xia Le discovers that his skills can be cast on an absurd scale, letting him command vast armies of skeletons. As he battles powerful monsters and clashes with forces from both Hell and Heaven, he turns their own mechanics into opportunities to grow stronger.