Olajide Olayinka Williams “JJ” Olatunji, better known as KSI, is an English YouTuber, internet personality, musician, and boxer. In 2019, he was ranked second by The Sunday Times in its list of the top 100 UK influencers. He is also part of the British YouTube group known as the Sidemen.

KSI registered his main YouTube account in 2009 and built a following posting gaming-commentary videos of the FIFA video game series. As his fan base has grown, his YouTube content has diversified to include vlog and comedy style videos.