Markiplier is the online alias of Mark Fischbach, a popular American YouTuber known for his video game playthroughs and comedic commentary. He began his YouTube career in 2012 and quickly gained a large following due to his engaging personality and entertaining content. His channel features a variety of games, including horror titles like Five Nights at Freddy's and indie games. In addition to gaming, Markiplier is involved in various charitable efforts, often hosting live streams to raise money for different causes. He has collaborated with other YouTubers, such as Jacksepticeye and PewDiePie, and has expanded his brand to include merchandise and voice acting in projects like The Markiplier Show.