a devoted follower
acolyte - follower
An ‘acolyte’ is somebody who attends or assists a leader or figure of authority. Such people tend to be unquestioningly loyal, so much so that the word implies servility and an unhealthy devotion. It also has religious connotations, suggesting blind faith. Typically used disapprovingly.
The politician is surrounded by acolytes who agree with everything he does and publicly attack anybody who says anything against him.
I respect my boss but I’m not her acolyte. If she says something I disagree with I will say so.
Kevin is that musician’s most fervent acolyte. He’s travelled around the world watching him perform live.