A person who follows or adheres to someone or something; a follower, adherent, or imitator; can be neutral or slightly pejorative depending on context.
その新興の指導者には熱心な追随者が多かった。
The new leader had many enthusiastic followers.
彼は流行に敏感で、有名人を真似する追随者だ。
He's sensitive to trends and is a follower who copies celebrities.
新しい理論には賛成する追随者と批判する人がいる。
The new theory has followers who support it and others who criticize it.