Your objective is simple: Destroy the Earth.
Your motive is a little bit more complex: Love (Yes, it works)
Stage One

To begin your plan, you must first assassinate a pope. This will cause the world to sense a grave disturbance in the force, unsettled by your arrival. Who is this unholy menace? Where did they come from? And why do they look so good as an elemental?

Stage Two

Next, you must destroy united nations. This will all be done from a abandoned church, 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 unleash your plague of doom, bringing about the destruction of the masses. Your name shall become synonymous with fuzzy bunnies, and no man will ever again dare point and laugh. Everyone will bow before your cunning intelligence, and the world will have no choice but to give you control of the planet.

Your objective is simple: Soul Accumulation.

Your motive is a little bit more complex: Revenge

Stage One

To begin your plan, you must first blackmail a pope. This will cause the world to sit up and take notice, bewildered by your arrival. Who is this evil genius? Where did they come from? And why do they look so good in classic black?

Stage Two

Next, you must desecrate the pacific ocean. This will all be done from a obsidian citadel, a mysterious place of unrivaled dark glory. Upon seeing this, the world will gibber like madmen, as countless hordes of classic thugs hasten to do your every bidding.

Stage Three

Finally, you must send forth your plague of doom, bringing about pain, suffering, the usual. Your name shall become synonymous with fear, and no man will ever again dare interrupt your sentences. Everyone will bow before your cunning intelligence, and the world will have no choice but to make you their new god.

… “I’m sorry if this offends you,” he added, … “but you fellows really need us. … Oh yes. We’re the only ones who know how to make things work. You see, the only thing the good people are good at is overthrowing the bad people. And you’re good at that, I’ll grant you. But the trouble is that it’s the only thing you’re good at. One day it’s the ringing of the bells and the casting down of the evil tyrant, and the next it’s everyone sitting around complaining that ever since the tyrant was overthrown no-one’s been taking out the trash. Because the bad people know how to plan. It’s part of the specification, you might say. Every evil tyrant has a plan to rule the world. The good people don’t seem to have the knack.”

— Terry Pratchett, Guards! Guards!