Opheli Meidan (Oh-fell-eye may-dan) is one of the first Trolls we are introduced to in the comic, she seems to be somewhat rude, pushy, possibly a lesbian, and overall a general menace who will push to have things her way because she feels as though the knows what is and isn't meant to be. 

For her I imagine her having an assertive, higher pitched voice, maybe even a little shrill.