Jeff Zirlin, widely known by his online handle Jihoz, is a co-founder and Growth Lead at Sky Mavis, the Vietnam-based studio behind Axie Infinity – one of the most influential blockchain games ever built. Before pivoting to crypto full-time, Zirlin worked in investment research and finance, an experience that shaped his later approach to angel investing in early-stage Web3 projects. He became a prominent figure in the crypto-gaming space around 2018 when Sky Mavis was founded, and by 2021 Axie Infinity had turned him into one of the most visible operator-investors in the sector.
Zirlin is not a fund manager in the traditional sense. He operates as an angel investor, deploying personal capital into projects that align with his conviction in gaming, consumer applications, and infrastructure supporting onchain economies. His portfolio of roughly 16 known investments skews toward early-stage teams building at the intersection of gaming and decentralized finance. Public information about the exact size of his deployed capital or AUM is limited, as is typical for individual angel investors who do not file public disclosures.
Notable investments
- Axie Infinity / Sky Mavis – as co-founder, his primary operating bet. Axie became a global phenomenon in 2021, reaching over 2 million daily active users at peak and generating hundreds of millions in marketplace fees. axieinfinity.com
- Yield Guild Games (YGG) – the Philippines-based gaming guild that onboarded tens of thousands of play-to-earn players in Southeast Asia during the Axie boom. Zirlin was an early supporter and the two organizations had deep operational ties. yieldguild.io
- Ronin ecosystem projects – as a key figure behind the Ronin sidechain (Ethereum-compatible chain built for Axie), Zirlin has backed multiple projects launching on Ronin, including DEXes and gaming studios building within that ecosystem.
- Various GameFi and NFT-native startups – Zirlin has publicly mentioned backing early-stage gaming studios and consumer-facing NFT platforms, though specific names and deal terms for many investments are not disclosed publicly.
Team
Sky Mavis was co-founded by five people: Trung Nguyen (CEO), Aleksander Leonard Larsen (COO), Andy Ho (CTO), Tu Bui (CFO), and Jeff Zirlin as Growth Lead. Zirlin studied at Yale University and came from a background in equity research before joining the crypto space around 2017–2018. He is based primarily between the United States and traveling to the Sky Mavis hubs in Southeast Asia. His public presence on X (Twitter) remains one of the most followed among GameFi founders, and he frequently comments on gaming adoption trends and onchain consumer behavior.
Recent activity
In March 2022, the Ronin Network suffered a $625 million exploit – at the time the largest hack in DeFi history. Attackers used compromised validator keys, and Zirlin's personal accounts were part of the social engineering surface. Sky Mavis subsequently raised $150 million from Binance and other investors to reimburse affected users, a move that preserved community trust. By 2023–2024, Sky Mavis refocused on rebuilding the Ronin ecosystem, attracting new game studios and expanding the chain beyond Axie Infinity. Zirlin has been vocal about transitioning Axie from a single dominant game to one title within a broader Ronin gaming network.
Through 2025 and into 2026, Zirlin's angel activity has remained focused on consumer crypto – specifically projects that can attract non-crypto-native users through gaming and social mechanics. His geographic interest spans Southeast Asia (where play-to-earn adoption first scaled) and the United States. He represents a relatively rare profile in crypto venture: an operator-angel who built one of the sector's most-studied products firsthand and now backs others attempting similar distribution breakthroughs. Public information about new deal activity in 2025–2026 is limited to occasional mentions on social media rather than formal announcements.