What is "gradeaundera"

GradeAUnderA (short for Grade A Under-Achiever, commonly referred to as Grade) is a British comedian best known on YouTube for his comedic rants and commentary on a diverse variety of issues. Grade also livestreams on Twitch, usually playing video games. He kept his real identity anonymous until his 2 million subscribers special, and uses drawn characters dubbed Grade and Under to show expressions and actions in his videos.