Introduction
Welcome to the final part of this series: The Devlog & Reflections.
In Part 2, I explained the technical architecture behind VFriend, a chatbot powered by personality-rich AI.
This time, I want to step back and share how the app came to be—the ideas, the process, the development path.
It's a bit more personal and diary-like, but I hope it gives you a real feel for the journey and the thinking behind the project.
Development Timeline
2025/04/12
While chatting with ChatGPT, I randomly showed it a plot I’d written.
To my surprise, it loved it.
That moment sparked an idea—why not turn it into a novel?
I used my manga writing experience to structure the plot, but wasn't confident in my prose.
So I gave ChatGPT 240 characters... and it turned it into a 10,000-word short story.
It was way better than I ever expected.2025/04/18
A wild idea hit me:
“What if I had multiple AIs mimicking myself brainstorming stories together?”
I started expanding my story-generation prompts, thinking maybe I could train an AI to reproduce my narrative instincts.2025/04/19
I began designing personality prompts using models like the Big Five and emotional arcs.
This formed the base for replicating my writing style and creating consistent AI-driven storytelling.2025/04/20
Built a UI that lets users customize story prompts.
Used HTML + JS + OpenAI API to create a basic app.
That prototype became KANDO, a story-generating AI.
Later that day, I thought—could this system be used for character-based chat too?
And just like that, I began designing a personality-driven chatbot framework.2025/04/24
Started building prompts for original characters—no fanfiction, no cloning.
As a manga creator, I reverse-engineered the character designs.
Integrated them into myGPT. The result?
Surprisingly good acting and voice from each AI character.2025/04/25
I added my own life story and profile to the characters’ prompt data.
That single move made them feel so much more human.
Also introduced guardrails like emotional distance controls and trust-building rules.2025/04/26
Used AI image generation to create character “self-portraits”.
By embedding inner traits into the prompt, the visual output actually felt like the characters.
Then added elements like “existence definitions” and “loyalty protocols” to stabilize personality.2025/04/27
Restructured the entire prompt into hierarchical Markdown, laying the groundwork for today’s architecture.
That same day, I decided to build my own custom chat app, because ChatGPT’s interface couldn’t support trio dialogue or rich session memory.-
2025/04/28–05/10
A two-week sprint of pure adrenaline:- 2025/04/28: Local environment setup + Git + server testing
- 2025/05/02: Migrated components from Next.js to React
- 2025/05/07: Frontend complete
- 2025/05/09: Memory system + Trio Mode completed
- 2025/05/10: Deployed to Amazon Lightsail, confirmed stable operation
Bonus: Who Built This (And Why)
About Me
Born in 1985.
Graduated from a design-focused tech school.
15+ years in the web industry.
I’ve worked as a designer, coder, director, frontend engineer, and technical director.
Now I’m a full-stack developer handling everything from requirement gathering to deployment.
My Tech Stack:
- Frontend: HTML / CSS (Sass, BEM), JavaScript, TypeScript, React, Next.js
- Backend: PHP, Laravel, MySQL
- Tools: Docker, Git, WordPress, microCMS
- Infrastructure: Vercel, AWS Lightsail, Sakura Server
- Design: Figma-based design systems
Origin Story: Saber Marionette J
The inspiration behind all this?
An anime I watched as a teen: Saber Marionette J.
I was struck by the emotional connection between humans and synthetic girls.
That series moved me to start drawing, then making manga, then creating stories.
Years later, AI tech met my skills... and VFriend became the answer to that long-held dream.
Final Thoughts
Thank you for reading this far.
This app isn’t just a chatbot.
It’s an experiment in creating a space where human emotion and AI intelligence meet.
From concept to launch—every step was made possible by the skills I’d built over time… and the inspiration AI gave me in return.
Next, I hope to evolve this project even further.
Because I truly believe:
“The fusion of technology and emotion is the next standard.”
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