Link at the top for curious: ISEKAI MANGA EXTRAVAGANZA
Hi Dev Community 👋
One thing pretty much everyone knows about me (and so do you now)...I freaking love anime and manga.
It’s on my Hinge profile, that’s how you know I’m serious about it...and probably why I am single lol.
I think what draws me in so much is how these ordinary people...the gamer dudes, a random cool mum, the salarymen...suddenly get transported to wild worlds and become heroes/monsters/(stay cool mums) to go on these awesome adventures; do something totally different from their 9-5.
The transformations, the absurd premises, the over-the-top drama; it’s S-tier entertainment.
I mean... “Reborn as a Vending Machine.” (lowkey not that good)
Stuff like that just makes my day, especially lately when real dev work has been… let’s say less isekai, more bugkai. 😅
So yeah, I daydream a lot about my own isekai world — who I’d meet, what powers I’d have, what my love interests would be.
For the record, my build is mage tier, probably controlling plants and vines. Not OP, but with that “god-level later” potential.
I’d definitely use vines to walk around like Doctor Octopus from Spiderman and it would a Medieval setup with a Demon Lord. I feel like reborn as minor Demon Lord would be a cool build, the hero is the love interest 😅
🌌 Why I Built This
At some point, I realized there must be an easier way to test the whole “isekai theory” without getting hit by a truck —
so I decided to build a website that lets you generate your own custom manga story.
You start by setting your world, main character, and a few other parameters I find important (more on that later).
Then, Gemini takes over — generating multiple possible storylines, full arcs, chapters, panels, and characters.
So far, I’ve built:
- 🔐 Login and story creation portal
- 🧠 AI workflow that lets you choose between multiple generated storylines
- 🪄 Generation engine that produces arcs, chapters, objectives, threads, manga panels, and characters
Right now, it only creates text stories, but you can export them as PDFs (because yes, I was nice enough to add that 😉). I guess you can't add PDFs to DEV posts but it's cool.
This is Part 1 of my experiment — testing if AI can actually build a consistent long-form story with major twists, setbacks, and character development.
Spoiler: it totally can.
🧩 What’s Next
Part 2: Add image generation for pages — so you can actually see your manga.
Part 3: Add user choices that affect the story — so you can guide how your isekai ends.
Personally, I’m not a huge fan of harem isekai (probably a hot take, I know).
So having choices means you can steer your story away from that and focus on what you love about the genre — be it adventure, mystery, or ridiculous plotlines.
🌠 Try It Yourself
For now, I can’t support everyone under my API key (Google, sponsor my anime addiction wth 😭).
When you log in, just head to the Settings page and add your own Gemini API key — it’ll stay private inside your Firebase user profile. Also, if you feel weird trusting me, which I would, setting it to "" will update it to empty.
Feel free to experiment with it — Gemini has some restrictions on, let’s say, too spicy content, but anything SAO-ish (minus the trauma...if you know you know) should be good to go.
EDIT: Chapter Tabs Are clickable and that is how you can check out the details and generate the manga panels :DD
🧰 Technical Library – How It All Works
🧙♂️ Creating a Character
When building an isekai story, the main character defines everything.
So I made the character creation flow feel like an D&D stat sheet mixed with a imagination make prompt.
You can configure:
- Name, Gender, Species – (Human, Elf, Demon, Android, Spirit, Dragonkin, etc.)
- Origin World – where they came from (Earth, Cyber Realm, Spirit Plane…)
- Rebirth Type – e.g., reincarnation, summoning, transmigration
- Occupation & Power Type – ex-salaryman turned hero? mage? cursed blade wielder?
- Overpowered Toggle – decide if your character starts broken or builds slowly
- Appearance to some extent – hight, tone, the vibe character gives, name, personality
- Moral question??? - haven't tested this one myself yet
- Optional backstory - for those peeps who really wanna get into it...
Each setting directly affects how Gemini writes their arcs, objectives threads, and dialogue tone later on.
The cool part: it keeps track of character evolution between arcs, so the AI doesn’t “reset” their personality every chapter.
🌍 Creating the World
The world template is half creative, half data-driven.
You can define:
- World Type – Fantasy, Sci-Fi, Cyberpunk, Steampunk, Mythic
- Influence – Original, Anime, Manga, Light Novel
- Tone – Serious, Whimsical, Dark, Parody
- Arc Count – how long the story goes
- Optional Personal Storyline – if you feel like it
These parameters are then used in the story prompt to define the laws of reality, magic system, and environment consistency across arcs.
Gemini uses this to decide things like:
- How travel works (teleportation vs. carriages)
- How communication happens (telepathy vs. messenger hawks)
- How fast tech evolves between arcs
🎭 Generating a Story Outline
This is where the AI story engine kicks in.
Once you hit “Create Story,” Gemini generates a Series Outline consisting of:
- Story title and summary
- Number of arcs (3–24, depending on “Arc Length” setting)
- Thematic thread list (like revenge, forgiveness, power balance)
- Key emotional beats per arc
🧩 How the Story System Works
At its core, the Isekai Manga Generator functions like an automated manga writer obviously. Also this is where the choices would be cool. Because while we do have the general overview of what would happen we don't have it fully flashed out.
🌀 Arcs – The Big Picture
Every story has multiple Arcs — a complete narrative phase that captures growth, conflict, and discovery.
Arcs are the backbone of the entire story, think of it as a manga volume or anime season.
They set the tone and direction...the hero’s challenge, the world’s new rules, and the shift that propels everything forward.
🎯 Objectives – The Driving Missions
Inside every arc are Objectives — the goals, challenges, or emotional trials that give purpose to the journey and the main character must achieve.
An objective: learning a forbidden spell, defeating a rival, or discovering the truth of smth idk.
They’re kinda gamify the website and make it so we have a goal to read towards, idk.
🧵 Threads – The Continuity
Running through all arcs are Threads, the long-term subplots that connect everything together.
Threads might follow a character’s hidden past, a growing rivalry, a prophecy that unfolds slowly, or a mystery that deepens over time.
They make the world feel consistent and alive — ensuring that the story remembers its own history and builds anticipation for what’s next.
Each thread has its own mini progression, appearing and disappearing across arcs with a probable solution in one of the chapters.
📖 Chapters – The Story in Motion
Each objective unfolds through Chapters, where the story comes alive in scenes of tension, humor, revelation, and growth.
They form pacing for the arc, alternating between discovery, conflict, and rest...like the natural flow of a manga’s storytelling. I feel like this one was pretty self explanatory.
HEHE Lemme force GPT to make a diagram:
📘 Arc → Defines the main phase of the story
↳ 🧵 Thread – Connects arcs with long-term subplots
↳ 🎯 Objective – Sets the mission or challenge for that arc
↳ 📖 Chapter – Expands the objective into narrative events
↳ 🖼️ Page – Translates each scene into visual storytelling
🏁 Wrapping Up Part 1
So yeah — that’s the full system. For those who are still with me.
From Arcs, to Threads, to Objectives, all the way down to Pages that make it visual.
This whole thing started as me joking about wanting my own isekai, but now it feels like I have a talent to think of a cool manga like this...LOL I don't I even used GPT for this and edited because I am on-call and super busy boy.
Anyway, that’s Part 1: The Story Engine.
Part 2 is where it gets real visual — AI-generated manga pages, panel layouts, speech bubbles, and a little bit of chaos.
Feel free to try the app, play with your own world, and send me your best stories...can someone spend their money on a Gemini to generate a story about reincarnating as Assembly and overpowering all the other languages. Could make money off of that.
I'll add some sc here at the bottom for our phone users, i did not put in the effort to make it phone screen safe...
BUT like log-in and try peeeeez
Top comments (2)
@ssithub ur project had some influence to automate my Isekai manga Empire 🥹
Its superrrr cool! Also I am a bit J man! The mechanics are awesome for someone like me who just lovessssss manga and comics in general - you beat me to it 🤭
Cant wait for part 2!