This is the story idea I have so far:
Long after the hero Lars Halford freed the humans from the clutches of the Tainted Coil, a new age of prosperity began where heavy metal reigned supreme throughout the land. The human forces making up Ironheade were approached by a charismatic leader known only as The Man and his vast empire, built by using the power of music concentrated into magical disks with seemingly boundless potential. The forces of Ironheade accepted, and for a time they enchanted the disks with their music to rebuild their civilization from the ruins of the war.
But The Man had different plans for them. He wanted Ironheade to change their music for the benefit of his empire. He wanted to control their music. He wanted them to bow to the will of him and his mistress, a powerful sorceress named Lady Gora. But Ironheade would not do this, for this sort of music was shallow and artificial, and reminded them too much of General Lionwhyte and his hair metal militia.
The Man was furious at their refusal, and he sent another faction their way. This faction of obsidian-skinned humanoids, known as the D-unit, their disks containing spoken word songs that could hardly be considered music by any standards, approached a pliable human named Frederick Durstein and collaborated with his knowledge of metal to create an unholy abomination of music that disgusted Ironheade. The Man was pleased with Frederick and his new creation bowing to his will, and declared his music to be the new metal.
The Man wanted Ironheade erased from this world, and using the dark magic possessed by Lady Gora, the rural ancestors of Ironheade and their cattle were resurrected into a state of neither life nor death, and with their livestock and repurposed farming machinery they became the willing footsoldiers of The Man's army.
Lady Gora, Frederick Durstein and the D-unit, and the rural undead waged war against Ironheade. Being outnumbered and The Man having denied them of any further music disks to use, Ironheade was broken up and their once glorious kingdom crumbled. It seemed that Lars had sacrificed himself in vain.
Ironheade was no more, and The Man would continue to exploit the unwashed masses of his own empire for all it was worth. But not everyone gave up on the heavy metal dream. Four metal warriors collectively known as the Men Of War sought out and recovered the sacred amulet of Ormagoden, once worn by the son of Riggnarok, and cried out to the metal god. The spirit of Ormagoden heard their call, and he would travel far into the future, into the era that the son of Riggnarok had lived in. There, five metal musicians would be chosen by fate to be taken back to the time of the reign of The Man, where they were destined to create a new heavy metal army, and stick it to The Man...
We obviously need people to play these musicians from the future: a singer, a guitarist, a bassist, a drummer, and either a keyboardist or a second guitarist. And if we get enough people we can have others play the other characters: The Man, Lady Gora, Frederick Durstein, the D-unit, the rural undead, and the Men Of War.