David Baszucki, the founder of Roblox, better known as his avatar, Builderman, has recently entered the billionaires club after the continued success of the game.

Those items generated about $121.2 million in revenue last year, the company said. Roblox is starting with 40 of its most popular characters, including Builderman.

Roblox’s ‘Builderman’ CEO Heads to Wall Street With an Army of Young Game Creators The company runs a free social platform with videogames made by its own players. Its stock-market debut ...