Opposition character

a character that wants to prevent buck from fulfilling his concrete goal

this may be a rival,an enemy or an adversary

the opposition character need not be a villain

in some romances the opposition character is the loved one who must be persuaded to love in return.

some opposition character pairs

transgressor vs enforcer

lover vs resistant beloved

persuader vs person resistant to being persuaded

rival vs rival

enemy vs enemy

transgressor vs victim