The co-founders of Gemini-owned non-fungible token (NFT) marketplace Nifty Gateway are stepping down and leaving Gemini to eventually start another company.

Duncan Cock Foster, who founded Nifty Gateway alongside his twin brother Griffin Cock Foster in 2019, said he and his brother would be replaced by VP of engineering Eddie Ma as technical leader, and director of collector services and growth Tara Harris as non-tech leader, and that he and Griffin would continue with the company as advisors to ensure continuity.

Gemini acquired Nifty Gateway in late 2019, with Duncan and Griffin teaming with another set of twins at Gemini – Cameron and Tyler Winklevoss – to provide the backend infrastructure to allow traders to purchase NFTs with fiat.

NFT trading volumes have fallen 94% in the past year, however, and Gemini has faced a series of challenges, notably having to halt withdrawals by its Earn customers because of problems at its partner on the product, Genesis Global Capital. Genesis filed for Chapter 11 bankruptcy last week, with documents showing that it owes $766 million to Gemini. (The parent company of Genesis is Digital Currency Group, which also owns CoinDesk).