In my opinion "By Destiny" and "By Chance" are the two of the
lesser ways to do it! Better ways to "become" a hero are by measured choice, by displayed merit, by earning (or taking) it somehow, or especially by their unknowing (but motivated) decisions - any of these, combined with a strong conviction, can create great heroic characters. Often there's some kind of birthright or prophecy mixed into that as well (even in good stories), but I feel it's complete unnecessary.
Minor, vague spoilers for Harry Potter and Tales of Symphonia in this following paragraph. Skip if you're extremely sensitive to spoilers and plan to enjoy those works.
Good examples of heroes who weren't there by chance or by destiny, and therefore really connected with the audience, (if I remember the details correctly) include Odysseus from Homer's
Odyssey, Claret from
Skyborn, Callum and Reila from
The Dragon Prince (who sort of had destinies as different kinds of heroes, and choose their own path instead), and Hermione Granger from
Harry Potter (interestingly, Harry himself
is part of the prophecy, but it's Hermione, who becomes a hero through merit and choice, who ended up being the most beloved character).
Popular movies like
The Social Network (Mark Zuckerberg) and
Rocket Man (Elton John) are essentially character studies, where the "plot" is only there to service the character's development, which is also the case in the anime
Death Note (Lyte).
Tales of Symphonia violently subverts the ideas of fate and the Chosen One, and its story and cast are one of the most popular in the history of RPGs.
Log Horizon presents a similar isekai setup to what you usually see in the genre, but its main character Shiroe starts in the same position as the thousands of other people who got sucked into the game, and it's his cunning and ambition that eventually earn him a special role, rather than being "fated" by the game or just being "really OP" (see Kirito from
Sword Art Online)
And when the hero's beliefs, personality, talents, and flaws drive the story around him - rather than some kind of predetermined "destiny" or narrative convenience - that's when you have great storytelling.
Game of Thrones went off the rails a few times, but for the most part it really nailed this - almost everything that ever happened to a character (sans the White Walkers, which were dumb anyway) happened directly because of the nature of that character or because of the nature of another character. If you think about each Stark family member (and focus on the first six seasons), you don't have to squint to see how their character traits directly led to the circumstances they found themselves in.
One of my golden rules of making a good RPG is that "
Weak plots are driven by Convenience, Good plots are driven by Motives, and Great plots are driven by Characters". To put it less vaguely:
- Weak plots are driven by Convenience - the characters are simply asked or forced to do something and accepts the task.
- Good plots are driven by Motives - the characters have a convincing desire or need that drives them to do everything that they do.
- Great plots are driven by Characters - the events that unfold only do so because of who the characters are, and replacing the cast with a different cast would make the general plot impossible.
I think that "destiny" falls mostly into the Weak Plots driven by Convenience category (although it depends on how hard the destiny is "hammered" onto the audience), and "chance" will fall somewhere between the Weak and Good categories, depending on how much sense it makes for the character (with their motives and abilities) to become a hero in that moment of circumstance.