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Everything is becoming interactive, Lucky Zhang told me from his Belmont hacker house. Now he's doing the same thing to TikTok/YouTube, turning passive video watching into living inside the content.
Lucky is no stranger to building successful content platforms. He built and sold a TikTok competitor in Latin America, then created Vietnam's largest music platform.
His current startup, Sekai (backed by a16z), lets users create and live inside AI-generated worlds through chat-based interactions. The app now has 1 million users who spend 2 hours daily living inside these worlds.
Let’s break down Lucky’s playbook today 👇.
The Genesis
Lucky has been obsessed with content platforms for over a decade, and his track record proves he understands how to build them at scale.
In 2018, he noticed TikTok wasn't taking emerging markets seriously. He built a TikTok competitor targeting 400 million Spanish speakers in LATAM. After two years, it became the largest local short-form video platform in the region, and ended up getting acquired by TikTok.
A year after the acquisition, he left TikTok and moved to Ho Chi Minh City to create a music platform for Southeast Asia. He struck gold once again, and his music platform quickly became Vietnam's largest music platform and second-largest in Indonesia, while owning 2 of the 3 largest media label companies in Vietnam.
After ChatGPT launched, Lucky saw the next big content shift.
Google search once felt magical—type a query and Google surfaced the most relevant results. Then came ChatGPT, where people could chat and explore ideas in depth. Lucky believed entertainment would follow the same path.
For the last decade, people consumed content passively on TikTok and YouTube. With AI, they can now interact, engage, and even live inside the content.
Lucky decided to build Sekai to do just that: turning passive consumption into living experiences.
Sekai’s product journey
Lucky started with hardcore anime fanfiction communities, the group with the strongest unmet desire. They craved the chance to step inside anime worlds, but until then had no way to experience it firsthand.
This niche is also massive. The anime market has exploded to $50B+ globally, with Crunchyroll viewership doubling to 300M fans worldwide between 2020-2022. Netflix reports that over half of its subscribers watched anime content in 2022.
p.s. Btw highly recommend reading this a16z post on recent developments in the anime space
1/ MVP
Sekai’s first app was simple. Users could fill out a form describing scenarios like "Go eat ramen with Donald Trump in the Genshin Impact world." The system would generate videos with basic avatars and text overlays.
The magic was in the specificity. The AI would generate Donald Trump commenting "This is tremendous, this giant bowl of ramen" while standing in an anime setting.
For the first time, users could see their exact imagination come to life.
2/ Evolution to world building
One key insight from the MVP was that users didn’t want short video clips. They wanted to actually live inside these worlds they created.
"If you are already living in a world that you wanna live in, you don't wanna just stay there for 15 seconds, you wanna live your everyday life."
Sekai shifted from generating short videos to creating immersive, persistent worlds.
Instead of a single ramen scene with Donald Trump, users could step into the Genshin Impact universe and interact with multiple characters over time. They could interact with the whole ecosystem of friends, rivals, and relationships that made the world feel alive.
Characters also became proactive. They could reach out with messages like:
“Hey, let’s go to KFC.”
“Let’s beat Donald up tomorrow. Let’s practice.”
Inside Sekai’s 1M user growth playbook
1/ First 1,000 customers
Lucky started with systematic content creation across anime subreddits, with a focus on Genshin Impact.
His team posted 30-40 pieces of content daily across different anime Reddit communities, tracking every single post in spreadsheets with daily team discussions.
Track upvotes, comments, and click-through rates for every post
Identify which content types performed best in which communities
Learn community rules and build karma to avoid bans
Double down on successful formats and abandon what didn't work
Several posts achieved thousands of upvotes, each driving hundreds of users.
On top of piggybacking on Reddit’s traffic, they also started building their own community on Discord, which now has 10K+ members.
P.S. I wrote an entire playbook on how to get customers from Reddit. Check it out here.
2/ Influencer marketing
After reaching 1,000 customers through Reddit, Lucky experimented with influencer partnerships.
Big influencers flopped completely, but they found success with micro-influencers:
<1,000 followers
Paid $5–10 per video
Why it worked:
Micro-influencers joined the Discord and became active advocates
Content felt authentic since they genuinely used the product
They had higher trust with their small but engaged audiences
They replied to every comment, fueling organic buzz
This strategy fueled authentic amplification rather than forced promotion. Followers noticed the difference, growth compounded. One micro-influencer even joined the team full time!!
Over time, organic UGC content starts driving most of the growth. Users would create and share content on TikTok and YouTube showcasing new features and the worlds they built.
3/ Current traction
Today, Sekai has grown to over 1M users, with active users spending 1.5–2 hours a day inside the worlds they’ve built. The company has also raised $10M from a16z, A*, and Mayfield.
What started with anime has since expanded to include content around celebrities like Taylor Swift, sports like the NBA and WWE, and characters from hit Netflix shows.
Current challenges
1/ AI costs
With 1M+ users generating AI content, computation costs are massive. Unlike typical social apps where content creation is free (users upload photos), Sekai must generate every piece of content using expensive AI models. This creates cost challenges that don't exist with traditional content platforms.
2/ Building stable AI agent systems
Not only are AI agents not cheap, but they are also unstable. Sekai team needs extensive evaluation systems to ensure they can handle millions of interactions while maintaining character consistency and world coherence.
3/ Content moderation and safety
Managing user-generated scenarios across millions of users requires sophisticated content moderation. The platform must balance creative freedom with safety, especially given the anime community's diverse content preferences.
Vision
Lucky’s vision goes beyond entertainment. Stories, films, and literature have always tried to transport people into worlds they can’t experience in real life. TikTok and YouTube let audiences step into others’ imaginations. AI now lets them step into their own.
Lucky believes AGI will arrive within 5–10 years, reshaping how people spend time. As work takes up less of it, people will crave new worlds to explore. He wants to position Sekai as the platform that can turn passive consumption into living experiences.
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See you next Tuesday,
Leo
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