Added a rough 'Mobile Suit Sheet'!
To clarify:
Characters can certainly have an impact on the setting. However, it still needs to be within the realm of possibility for an above-average human to accomplish, and altering the setting in a way that affects the way other people get to play is out of bounds.
A multi-chapter story about opposing a corrupt governor, gathering the resources and contacts needed to confront him, before eventually deposing him, would be a perfectly appropriate story arc. A single post where a PC immediately shoots all the world leaders and declares themselves king of the universe is not.
Likewise, when it comes to supernatural elements, searching for a magic item that heals wounds or reverses aging would be a great mcguffin to form a story around. Starting the game with a bauble that makes you completely invincible and gives you flight and super-strength and laser-eyes would render any conflict pointless.
Rising up in the ranks of a faction, working to undermine their leaders, and even gradually building a faction of your own are all viable plots. Completely hand-waving away any intrigue or struggle by revealing you have Dragonball powers and making the game about Kung fu ki-blast battles is not.
You can absolutely make a difference in the world. But the bigger the change you want to make, the more work it's going to be.

<Snipped quote by Letter Bee>
That’s covered in the first post. There is magic but it’s subtle
<Snipped quote by Smike>
Mostly open to interpretation. The southern mainland continent likely has some equivalent to the Aztecs or Incas, but I haven't really thought it out yet.