I think what you are struggling with in this statement is word order. It grammatically works, but you sound like you might be in the process of editing and revising. I always want to make what I say more specific, more precise, and I want it to demonstrate strong word economy.

I recommend:

• The author ___________ a variety of qualities in the character, ____________.

In your first blank, use this list to determine a very specific verb to use. In the second blank, list the actual character's name.

• employs
• models
• displays
• portrays
• demonstrates
• shows
• creates
• illustrates
• illuminates
• highlights

Each of these are stronger verbs than the MAKE that you were trying to use. As an English teacher myself, when I see students move away from using do, have, is, are, make, give and a few other verbs that apply to many situations, I am then able to see them use their vocabulary to its fullest potential.

I do not think there is necessarily anything wrong with the way you have put this.  But I suppose you could use any one of the following wordings:

• The author has the character show different qualities
• The author writes the character in such a way that (s)he shows different qualities.
• The characters' actions and words show different qualities.
• The way that the author portrays the character shows different qualities.
• The author causes the character to show different qualities.
• The character shows different qualities (and never mind putting the author in there.