Yes! The antagonist is called Morbus the Reprobate inb4 5000 masturbate jokes a Reprobate is a sinner who is not of the elect and is predestined to damnation. He can disguise as other people, but he has to kill them first and eat their bodies. In the story Morbus meets the main character in different disguises.
I do use command blocks all the way through my map for redstone, teleports, and dialogue.
The main character is just as @p so it's the minecraft player's username.
The plot for each of the different worlds will be
For the forest: an infection has broke out turning all the normal pigmen into zombie pigmen. Boss: 3 Ghasts on opposite sides of a room. You have to reflect their fireballs.
For the cave world: There is something wrong with the mine that makes the ore unmineable for the cave spider miners. Boss: Giant
For the water world: There is a drought in the squid npcs need water. Boss: Elder Guardian
For the desert world: I don't know yet for the boss or the plot. Ideas???