World of Warcraft Necromancer

Ordinary office workers inadvertently come to a balanced space – the continent of Azeroth, where plagues are raging, natural disasters are rampant, and wars between various races continue. And he, who was originally ordinary, also had the ability to summon skeletons and cast curses because he obtained the Necromancer’s career book, thus embarking on the road to becoming stronger.
Who is the mysterious death knight? What kind of secrets are there in the book that can withstand even the Lich King’s will?
After having the dual identity of human and undead, whether to join the Alliance or the Horde is a question.