Jack Paul 
Sam Blackshear, co-founder and chief technology officer of Mysten Labs, is stepping down from his day-to-day role. He is heading to Anthropic to work on defensive security research. The news came directly from Blackshear, and it did not take long to spread through the Web3 community.
Mysten Labs is the organization behind the Sui blockchain. Blackshear helped launch the company in September 2021 with four former Meta executives. The team set out to build a layer-1 network with a different approach to speed and throughput. Since then, Sui has become one of the more recognizable blockchain projects in the space.
A leadership shift at Mysten Labs
With Blackshear moving on, Mysten co-founder and CEO Evan Cheng will take over the technical vision for the company. That is a big responsibility, but Cheng is not new to the project. He has been leading Mysten since the start and knows the codebase and the team well. Blackshear said he has been happiest when doing hands-on technical work and exploring new problem domains. He sees this move as a way to do both. He also said he will remain close to Mysten and will stay involved with the Move Foundation, which focuses on the Move programming language.
Why AI security matters right now
The timing is interesting. AI tools are already being used to identify software vulnerabilities, automate phishing campaigns, and speed up attacks on blockchain infrastructure. The balance of power between attackers and defenders is shifting, and not everyone is ready for that. Blackshear said he wants to work on security at a time when that shift is happening. It is a defensive research role, not another AI product push. For companies like Anthropic, security work has become more urgent as AI models are used in both good and bad ways.
What happens next
Blackshear will not disappear from the Sui world entirely. He will keep some connection to Mysten as an advisor. That should help with continuity, especially around Move and the technical direction of the network. Still, this is a notable loss for Mysten Labs in terms of leadership depth. Blackshear was a core technical figure. Replacing that kind of presence is not easy, even with Evan Cheng stepping in.
The move also shows how much crossover there is now between the crypto world and AI safety work. People with deep technical backgrounds are being pulled in different directions. That may create pressure on blockchain teams to hold onto their founders. It may also lead to more cooperation between Web3 projects and AI labs. I think we will see more of this kind of movement over the next year.