Fate and Destiny are effing cool.
I mean, if they weren’t, we wouldn’t still be enamored with them after like, four thousand-plus years. Admittedly, some depictions of Fate and Destiny in fiction are lame, but that’s more a quality-of-writing thing than the concept itself.
Prophesies are a pain in the butt to deal with in-game. Why?
Honestly, because you don’t know how things are going to turn out.
That’s the beginning, middle, and end of the problem. You need rules and game mechanics to do a thing which you literally cannot do.
But you also literally cannot do magic or juggle flaming axes (though if you work really hard at the second one, you can), so what makes prophesy any different?
I think part of the problem is that like alignment, people are always fighting the concept of Destiny. Everyone is more or less guilty of this — players and Dungeon Masters alike. Fate is there to be fought, it’s the ultimate in immaterial foes.
Some pantheons put a god in charge of Fate, but the Greeks knew better.
Even the gods were subject to Fate.
And Destiny has irony on its side. Unlike most forces (narrative and otherwise), Fate can win ironic, as well as moral, or even just normal victories.
Now, there is a related problem in trying to work out what Divination does, but let’s come back to that. Divination is a similar problem, but mostly what we’re trying to figure out is how to mechanically determine future outcomes.
The easier, the better.
Let’s see if we can factor this problem.
What does anyone want a prophesy to do?
A prophesy addresses the question of, “what would happen if you could know how things were going to turn out ahead of time?” If you could “see the future,” right? Whatever “the future” might be in this context.
What if you knew the consequences of your actions before you took them?
“Will I ever acquire this artifact?”
“How will I acquire this artifact?”
“Will I live forever?”
“How can I rule the world forever?”
I mean, some of these questions might seem stupid, but you have to remember the people in fiction you generally call upon prophets and oracles. Generally speaking, people in positions of power who abuse their privileges get all the prophesies.
Fiction is not kind to them.
Secondly, prophesies in fiction tend to be used as narrative devices. I would call Destiny “primitive foreshadowing,” but that’s not being really fair to the concept, which is older than what we understand to – be – a narrative.
Well, here’s the thing.
Like anything the players decide to do — taking action-wise — a Prophesy (or any Divination, for that matter) should always add something to the game.
This should be a no-brainer, but remember what I said earlier about everyone fighting this concept. It’s what people – do – with this concept. Seriously, it’s where my idea of using Destiny AS alignment came from.
Even if you use dice to ultimately decide the content of a Prophesy, any use of Prophesy should be something relevant to the campaign, like how rolling any random encounter adds those monsters to a campaign.
“There are ogres now, okay?”
In the past, I’ve tried to create a “Mad Libs” version of Prophesy, but I don’t think that’s going to work. I have another idea hat breaks Prophetic targets into scope and such, kind of based on other “tiers” of magical effects.
Another thing that Prophesies tend to do is complicate things.
If you want to know how an Evil Overlord will be defeated, you almost always have to acquire a Chosen One or a Sword of Destiny in order to see it through. This is your responsibility for taking the “Fate” route.