Apocalypse: Mad Necromancer’s Troops

【A false Necromancer lacks troops and is hunted down by others.】
【A true Necromancer commands countless skeletons and becomes a ruler in their own right.】
After obtaining the Dual-Portal, Wu Heng discovered that the original world was overrun with zombies.
When the plan to become a profiteer failed, a new plan for survival began.
Wu Heng chose to become a 'Necromancer.'
Can't summon the undead in another world? The entire apocalyptic planet is a source of troops.
Can't survive in the zombie world? Then I'll live and learn skills in another world.
From that point on, the world witnessed an undead army equipped with modern weapons.
Natural disaster looms, with millions of skeletons.
Undying bone dragons, undead kings.
(Dual-Portal + Necromancer + Magic + Fantasy World + Undead Plague.)