In my first big novel-kind-of-thing I'm currently working on, I have a run-of-the-mill, super-non-special "Hero" - the Antagonist. A Jon Doe, someone, who knows how to handle everyday stuff and can defend himself in a brawl.
Pitched against him is my Evil Overlord of doom - the Protagonist. Not just your basic Evil Overlord of doom with stupid minions and a soft spot for big speeches, no. He is designed with Peter's Evil Overlord list in mind.
How should i have my Hero start going on an adventure to save the world from my Evil Overlord? How should i motivate him to even THINK about doing that? He is a regular human with no extraordinary powers or anything, while my Overlord has Legions of minions and follows Peter's List?
As an additional note, people around the world know of that one weird guy sitting on this Island with tons of friends (as they perceive it). His plan already started and somebody needs to try and stop him (and fail miserably).
The following is only for flavour, providing a couple more details for those interested, though is not mandatory to consider when answering.
Quick rundown on the world we're living in: It's a fictional planet orbited by 2 stars, a very lively world. It's a lot smaller than earth and is inhabitated by currently 800-900 million people. In terms of landscape, I'm gonna focus on the areas where a bulk of the story takes place: First, we have an Ice Desert, here we find the city the "Hero" calls his home. Think pop.~ 70.000. Buildings are made out of a mixture of Steel and Ice, though melting the Ice won't cause every building to collapse, it just looks nice. This desert hosts a couple other citys, all smaller though. Next, we have an Island, roughly 250km off the coast of the Ice Deserts main port-city (located ~20km southeast from Herocity). Here we find the lair of our Evil Overlord.
In terms of technology, the world is similar to earth shortly after the middle ages (~1550). Magic IS a thing. Although very rarely do you see a Wizard openly casting spells, as that would most likely alert one of our Overlords Minions and have him (the wizard) get an Arrow stuck in his forehead. Magic is weak, useful for everyday chores at best. Making small appliances levitate, lighter-sized flames, that kind of stuff. It requires a rune.
/this was noted to probably fit better on writers than on worldbuilding
/Edit: as Lauren Ipsum suggested, moved a lot of the detail to the end as optional flavouring for those interested in it.