Writing How long should I make this arc?

[WaterFish]

Talentless Hero: The Chosen Hero Is Unqualified

Lex had become the Chosen Hero. However, he didn’t gain any talents or blessings. Instead, he mocked by his peers. No way such a person was a ‘Hero’ like his Job had stated. Job Class: ‘Hero’. Stigmata Gifts: None. Innate Gift: ‘Empty’. Future: Worse than even an F Rank....

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I was starting my Magic Academy story with an apocalyptic event happening in a different city.

Just wanted to know whether I should make it short, fairly long, or simply as long as it needs.

Was wondering if dragging the initial apocalyptic event for too long might cause readers to feel bored or uninterested. I’m calling it an Academy story but the school the audience has seen until this point has been mostly closed off right now.

The main characters are running around in the midst of an outbreak and doing their own stuff.

Would this be too different from expectations and thus lose the reader’s attention?

That’s what I’m worried about.

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—Gallery: Celest Vagabond (Evil Principal)

 

[MatchaChocolate69]

My advice, but take it with a grain of salt, is to skip prologues whenever possible and, if needed, present them as flashbacks. The length depends. If it's not crucial to the story, cut it; otherwise, get to the action and write the essence, avoiding filler.

 

[WaterFish]

My advice, but take it with a grain of salt, is to skip prologues whenever possible and, if needed, present them as flashbacks. The length depends. If it's not crucial to the story, cut it; otherwise, get to the action and write the essence, avoiding filler.

Too late. 22 chapters into Arc 0. Can’t flashback this arc now

 

[RepresentingPride]

Write it like you want. What the point to give you a limit? Except if you have made yourself a minimum words count for each chapter you write, just write them how you want, you end it when you feel like it fit. If you want to drag this arc longer to write more detail about your characters or worldbuidling, do it. Some readers may be displeased by this choice, but the one who keep reading your story the next 100 chapters will prefer it since that add detail to the lore.
Except if you write for money, you shouldn't take decision based on your readers, you can take their advice and think about them if you want to use it or not, but you are the one who made the choice, they won't be the one writing the story, some small detail may be useless for them but since you know what happen in the future, you know it's important to add them in the story.

 

[BearlyAlive]

There's still the option to rename it and market it as a prequel if the prologue gets any longer.

 

[LilRora]

My advice is, consider why that arc is there in the first place. If it's supposed to be an introduction, then make it short. If something meaningful happens during it (to the plot that's directly relevant to the characters, I mean, not to the story in general), then you make it as long as you need to appropriately describe those important things.

My favorite writing rule is, start as close to the end as possible. To you, it's not exactly applicable, but if I paraphrase it into "make it as short as possible and say what you want to say", it becomes fairly self-explanatory, yeah?