The Lone Necromancer

Reading manga/manhwa/manhua The Lone Necromancer 나 혼자 네크로맨서 , ソロ降霊術 , The Alone Necromancer , The Only Necromancer , Solo Necromancer :
The world is ending. Monsters from legends appear everywhere. They eat people, conquer the streets, and begin to make dungeons in the buildings and subways. If you could choose one job in this decrepit world, what would you choose? For a “necromancer” extinction is my playground and death my wealth.