fan s or no s

[Unregistered]

Should the word preceding fan be an adjective or a noun?
Are these sentences correct?
I'm a tennis fan.
I'm a Little Mermaid fan or I'm a Little Mermaid's fan.
I'm a Batman fan or I'm a Batman's fan
I'm a Dragon Ball fan or I'm a Dragon Ball's fan
I'm a Mariah Carey fan or I'm a Mariah Carey's fan

[Anglika]

You would not usually use a possessive with 'fan" - I am a Beatles fan, I am a Batman fan, I am a Mariah Carey fan.