Vanessa Griffin was Chris Griffin's future wife from Stewie Griffin: The Untold Story. She was known to be very foul mouthed and bitchy. She forced Chris, Stu and Ron, into putting Lois and Peter into a retirement home, all so that she and to an extent Chris, could get the house. However, Lois, who clearly disliked Vanessa, had a time-traveling Stewie promise to make a side-trip on his way back to the past, and stop Chris and Vanessa from ever getting married, and thus keeping her from putting Peter and Lois in the home. Stewie honored the promise by stopping at the wedding, and blowing up Vanessa with a rocket-propelled grenade. As a result this leaves the marriage of Chris and Vanessa in doubt.
It is unknown how Stewie's alteration of the timeline, Susie Swanson's birth, Francis Griffin's death, Cleveland Brown's departure from Quahog, and the deaths in "And Then There Were Fewer", affect her meeting Chris.