What is "root" and why does it keep contacting different servers?

I have blocked this "root" [app/service/user] from accessing the network. However, I can find no specific answers as to what it is and why it attempts to contact only random servers. I use NetGuard to better control the network on my phone, that is where the screenshot came from. I have searched for days for an answer to my question, but there are literally millions of instances across the network and boolean searches only narrow it to tens of thousands. Should I be worried about malicious intent or just keep it locked down?