Who is actually the Scrum Master?

scrum master coach

The Scrum Master helps the team to be productive and use they creativity in order to deliver done, working software.

The main point here is that the Scrum master leads the team, but not command the team

The Scrum Master is a Coach. He is not a boss. The team members doesn’t need to report to the Scrum Master.
The Scrum Master is not a manager and doesn’t order to do anything. He is a leader and he need to figure out how to lead the team.