Sonja is a woman Quagmire meets when he returns a computer after it stops functioning in "Quagmire's Quagmire".
After she discover his tastes in porn are on the kinky side, they go out to dinner but he awakes the next morning to find out she drugged him in order to guarantee sex. Believing himself to be in love, their sexual encounters soon begin to wear on Quagmire as Sonja takes to dominating and humiliating him, beating him black and blue. He tries to get a message to the guys while out at The Drunken Clam but Peter is oblivious. Sonja shows up outside of the Clam and kidnaps him, stuffing him into the trunk of his car.
When Quagmire isn't seen for several days, his father, Ida Davis comes looking for him at Peter's and Joe mentions that they missed apple picking together. The guys search for Quagmire by going to all his usual haunts. Wandering into a seedy area, they find Sonja has a reputation and are directed to a storage center. Finding Quagmire, they are cornered by Sonja who takes Joe's gun. He calls her bluff and closes in. She pulls the trigger without result and Joe tackles her, admitting he keeps his gun unloaded following an incident the previous April.
Sonja is voiced by Rachael MacFarlane.