Bluebeard4 (Ivy Nye) is a person who worked on Kart Kingdom. 2leaksavege discovered him in October 2017.
When the game's closure was officially announced, he tweeted, "K appeared in #kartkingdom yesterday to hand out passports to over 14,000,000 users. It's been a great 5 years!" He attached his passport and a gif of his avatar in the game. During the closure party, he tweeted, "Today is the last day of #KartKingdom. I've loved everything that I've worked on, and the small but talented team of creatives and devs. But I will miss the users the most, reading their comments, reviewing drawings and watching them fill out their wiki over the last 5 years." Attached was a screenshot of his avatar and other players in the party room.