Your objective is simple: World Domination.
Your motive is a little bit more complex: Sadistic pleasure
Stage One
To begin your plan, you must first expose a chosen one. This will cause the world to choke on their food, confused by your arrival. Who is this nightmare beyond comprehension? Where did they come from? And why do they look so good in your wizard's robes?
Stage Two
Next, you must steal the moon (ooh, tides!). This will all be done from a obsidian citadel, a mysterious place of unrivaled dark glory. Upon seeing this, the world will give up, as countless hordes of animal minions (rats, birds, etc.) hasten to do your every bidding.
Stage Three
Finally, you must activate your great supernatural forces, bringing about the dead rising from the grave. Your name shall become synonymous with metal, and no man will ever again dare take your lunch money. Everyone will bow before your mystical abilities, and the world will have no choice but to give you control of the planet.