Opening scene:
Narrator "Before the time of mortals began, the Great One banished the demon horde into Hell, and to secure their imprisonment, he sealed them away with Adamantine..." [the video shows a demonic horde surrounded by magma and then the camera flies upwards through the beautiful adamantine, which sparkles in the light of the magma]
[at the top of the spire, the camera stops and the noise of metal hitting rock is heard... a crack appears with a dwarf's who looks through]
Narrator "But now... they are free."
[at first the dwarf smiles, then suddenly a demon [enter general description here] appears and kills him]
[camera follows a demon at blinding speed, the camera goes into bird's eye view and shows a fortress being torn apart]
Narrator "And only a group of the greatest heroes of the three races can stop them."
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Scene 2, a Tavern
Dwarf "Whaddaya mean there's no more Dwarven Ale?!"
You get the picture. The Dwarf would be a general berserker, the elf would be Cacame or a descendant of his and the human would be a priest or something who saw through the disguise of a demon pretending to be his/her deity.
Episode 1: Getting to the mountainhomes, while being chased by the demonic horde and blocked by a goblin fortress.
Episode 2: They all die. Horribly. We see a new dwarven kingdom arise, from a single fort. They sieze control of the elven and human civs and prepare an attack. The king and the other 6 dwarves are survivors of the battle in Ep1, alive because of "the heroes"
Episode 3: 3 races together charge the demons. In the end there's a ritual to summon Armok on the dwarven side, and since he hates the demons who don't worship him, he comes and massacres them.
Hmm... I might write a book on this actually. Maybe I'll even get to chapter 3, that would be a new record on my side.