Isekaied-Back to earth
Comment : You have entered the dungeon of Gwachun Station 1st Exit.] When former high school student Kang Woojin finds himself back on Earth after being forcibly summoned to another planet for 20 years, he soon discovers that Earth is not more the same place he remembered. With his original strength and age reset to the beginning, Kang Woojin returns to the path that will see him become the strongest Necromancer on Earth.
From the same author of: Seoul Station Druid
Disastrous Necromancer