Back in May, Nexon unveiled a rather intriguing project. Dubbed 'NEXON Replay,' the initiative opens up the vault of 20-year-old IPs—including Tactical Commanders, EverPlanet, Asgard, Dark Ages, and Elancia—to external developers, inviting them to craft and service entirely new titles based on these storied foundations. The secret sauce enabling this resurrection of two-decade-old nostalgia? Nothing other than the rapid evolution of AI.

I caught the nitty-gritty details firsthand at the NDC 26 stage. The session was led by Oh Se-hyung, the head spearheading Nexon's MapleStory Worlds business and IP licensing efforts. He pulled back the curtain on the origins of NEXON Replay, the rigorous preparations involved in prepping these ancient assets for third-party partners, and the road that lies ahead.

The catalyst for NEXON Replay was simple: the enduring, stubborn fandom that refused to let these 20-year-old titles fade into obscurity. "Even when services shut down or content dried up decades ago, the fans kept going," Oh explained. "IP is nothing without its community. We realized that Nexon sits on a treasure trove of IPs with active fanbases, and that is where the real opportunity lies."

Let’s be clear: you cannot simply dump two decades of digital detritus onto an external partner. The legacy code is a labyrinth, and determining which assets are actually usable requires a painstaking human touch. There’s the nightmare of personal data—résumés, workshop photos, and the like—hidden in the files, not to mention third-party SDKs, middleware without redistribution rights, and sensitive internal security protocols. It was a logistical minefield that seemed insurmountable until now.

By leveraging AI, even a small team can now sanitize source code and assets, stripping out the hazards while making the files ready for external developers. They established five strict clearance criteria: filtering out corporate and personal data like internal contracts and team photos; identifying restricted third-party middleware or internal SDKs; locking down security-sensitive areas like authentication logic and GM commands; purging sensitive logs; and finally, maintaining IP quality control.

The resulting system, dubbed the 'NEXON Replay Clearance,' is what makes this possible. "It is a system that packages raw data into a safe kit for our partners," Oh noted. "You feed it the original code and asset paths, the AI scans everything, flags the risks, and mitigates potential issues before they ever become a problem."

The work goes far beyond mere deletion. "Say there’s code for unit repair costs," Oh hypothesized. "A developer needs to understand how it works, but I can’t hand over the raw code. If the server flow or exception handling is exposed, it could compromise other live games. So, we read the logic, grasp the function, and rewrite the code from scratch. The partner gets the functionality they need, and we keep our internal secrets safe."

In short, NEXON Replay Clearance isn't just about scrubbing data; it’s about filling in the blanks. The team provides the IP package, which Oh describes as including "the licensing rights, comprehensive guidelines, organized assets, and reference implementation code."

They are going a step further by providing tools to aid the actual development process. They’ve introduced a RAG server (a tool that lets AI search and retrieve knowledge from a specific domain) packed with original source code and planning documentation. Because it’s based on Nexon-verified data, you get answers without the typical AI hallucinations.

Then there’s the image-training LoRA model. "For pixel-art games like Elancia, the workload is immense," Oh said. "Drawing everything by hand takes forever, so we are developing an assistant tool to quickly reference the original art style, color palettes, and silhouettes. It’s still early days for LoRA, so it will take some time before it's ready."

Finally, they are enabling browser-based ports. "Old games are hard to explain through documents, but easy to grasp when you play them," Oh noted. "By compiling existing code into WebAssembly, we can let people jump in directly from a web browser without installation. It helps with partner onboarding, lowers the barrier to entry, and acts as a bridge to pull users into these new, revived experiences."

This renaissance is only possible because of the convergence of AI and the mature UGC ecosystem. "In the past, the cost of reviving these IPs was prohibitive," Oh admitted. "But now, AI handles the heavy lifting—code analysis, file classification, and risk detection. The UGC scene is finally mature enough for small teams to build commercial-grade titles. The fans' memories are the raw material, and we finally have the tools to turn those memories into something playable."

The Replay team operates with a 'build-and-discard' philosophy for their internal tools. They’ve built custom solutions like 'Creator Lens' for reviewing applications and 'Merlin' for managing project context. "We build tools for a specific task and scrap them when the job is done to avoid a maintenance nightmare," Oh shared. "Merlin, for instance, was retired once Claude became integrated with our office tools."

The ultimate goal for NEXON Replay is to find developers who truly understand these originals, craft core experiences that spark new franchises, and eventually branch out into merchandise and media. "We are currently in the stage of vetting IPs, building packages, and onboarding creators for our first test cases," Oh stated. "The next step is to standardize this cycle so new partners can jump in without the friction."

Nexon remains convinced that there is still gold in these two-decade-old archives. "As long as fans remember, there is always room to build something new on those foundations," Oh concluded. "For creators, this is a new shot at success; for fans, it’s a chance to revisit their memories through fresh, modern content."