@Solipsist
The power to be "left alone unless you don't want to be" means you basically have agency in deciding how much involvement you want to have with the world. You show up in the world, and if you don't want to be involved in the world saving quest, that's fine, because you'll be left alone because you don't want to be involved in it, but if you want to be involved in the quest, you will be, because you don't want to be left alone when it comes to the quest. Likewise, rulers and kingdoms will ignore your existence, not bothering to tax or coerce you despite being from another world, unless you don't want them to, because, again, you get agency in how much involvement you want in the world. If a war occurs around you and you don't want to be involved, the power would mean the war literally ignores you like you weren't even there, so you could walk through an active battlefield with no ill effect beyond maybe some psychological trauma from seeing a bunch of people die, but even then, that would be on you, because that would mean you wanted to be involved in at least that much, so really, if there was a war going on around you and you had that power and didn't want to be involved, the war would completely ignore your vicinity and you'd be able to continue your life as usual, because it'd leave you alone; hell, you might not even find out there's a war going on, because you didn't want to be involved, so it left you alone.
Basically, it's the power that would be best for the "slow life" subgenre, because it literally lets you decide how much of what you want in your life. Hell, in its extreme form, it is a type of selective immortality, because even death will leave you alone unless you don't want to keep living.