Some say the undead rise when someone is not buried properly, but they are only myths written nowhere, not even in the enchanted books. They are fierce rotten creatures who still know how to hold weapons probably because some of their human memories still remain.
However, they are merely mindless monsters dominating the land of the Overworld, for they fell apart when Herobrine was defeated.
Notable characters (left to right):
Herobrine
Appearances: The Struggle, Cold as Ice, We Are the Danger, Goodbye
Bio: A legendary undead who commands the undead army. His only motivation is to destroy mankind.
Arsenal: He favors dual swords as his main weapon. He has the ability to manipulate lightning and imbue his weapons with shock capabilities. He can also dash short distances and teleport his way out of danger. However, his most powerful ability is to take control of the undead army and command them to his will.
Personality: Egocentric and irrational, his sole campaign to destroy all of mankind has driven him mad.
Blackbone
Appearances: Cold as Ice, We Are the Danger,
Bio: Military advisor to Herobrine and commands small units of wither skeletons.
Arsenal: He wields a giant sword, which possibly came from the Nether. His bone plating allows him to withstand melee attacks and bullets, but he has no match against magic.
Personality: Obedient and loyal to Herobrine.
See the next chapter for the Nether Horde
Infernius
Appearances: Wither Heart
Bio: An undead pyromancer who destroyed the Coven. Not much else is known about this mysterious entity's backstory.
Arsenal: Can control fire and has a wide variety of pyromancy spells. He can also fly around and charge at incredible speeds.
Personality: ????
See the next chapter for the Nether Horde