@speed yt channel 

(ShowSpeed) would be concise, engaging, and highlight his core content. It should include his name, a brief description of what he uploads (video games, especially Fortnite, with some music and possibly rap), and a call to action to subscribe. For example: 
"Speed, aka IShowSpeed, here! I stream and upload videos of me playing video games, especially Fortnite. You'll also find music, rap, and some crazy stuff. Subscribe for more speed!" 
Here's a more detailed breakdown of what to include: