The most impressive pseudonymous technology person I can think of to date is IceFrog, the brains behind the longest iteration of DotA 1 who Valve somehow uneart

The most impressive pseudonymous technology person I can think of to date is IceFrog, the brains behind the longest iteration of DotA 1 who Valve somehow unearthed to lead DOTA2 design. People have tried to discover who he really is for over a decade, and only have a guess for his real name and age. Given that people have known of him since 2006 (for a twitter account with ~100k followers and known lead for a game with a million MAU), in this era, that's super impressive.