How many forms does the villain Frieza transform through during his original saga in Dragon Ball Z?

How to get close to this number

Escalating transformation counts in this genre cluster between three and five — enough for a multi-stage confrontation and few enough that each stage gets a memorable design. Four is the middle of that band and the most common answer.

The inversion in the explanation is what makes this one interesting: the final form is the character's true, unrestrained body rather than a new power acquired. Each transformation removes a restriction rather than adding an ability, which is the opposite of how power escalation normally works in the genre.

That inversion is why the sequence is so widely imitated. A villain who has been holding back is more threatening than one who is growing stronger, because the audience learns that everything so far was not the real fight. The count matters less than the direction, and the direction is what the genre copied.