Neel Somani, 24, quit his job as a quantitative researcher at Citadel, a hedge fund, in February to work on a project that connected Luna’s underlying blockchain to Ethereum, another cryptosystem.

In April, Mr. Somani joined Terra Hacker House, a month-long program in a Chicago office sponsored by Terraform Labs and its investors, designed to incubate projects built on Mr. Kwon’s technology. Within weeks, Somani lined up $10 million in venture capital funding commitments that valued his project, Terranova, at $65 million. He was about to hire three employees, he said, and had 40 customers enthusiastic about the idea.

After the fall of Luna and TerraUSD, Mr. Somani and his fellow hackers initially thought that Mr. Kwon and his partners could turn the tide. But last Tuesday, Mr. Somani realized that it was over and felt relieved that he had not yet accepted the funding. He lost about $20,000 from Luna, he said, which he didn’t mind since he made money on other risky stock and crypto bets.

Over the past week, the hacker house offices have emptied. A Telegram group called Rebuilding Terra, with nearly 200 members, actively discussed how to save projects and funds.

Mr. Somani is optimistic. “For those of us who are crypto builders, the feast and famine mentality really comes naturally, and maybe that’s what drew us to the community,” he said.

On Thursday, he plans to show off his now-obsolete technology at the Hacker House Demo Day. Most of the other bands have left the program, he said, so he expects less competition for a top prize of $50,000.

“It’s in US dollars,” he said. “I asked.”

Kirsten Noyes contributed to the research.

Sound produced by Parin Behrooz.