Eva Jericho was Alfred Jericho's wife. Her maiden name was Dalloway.
She adopted one of Winnie Tyler's twin sons after Jacob Tyler abandoned his wife, naming him Steven Jericho. The child was sickly all his life, due to his brother Gabriel unknowingly drain energy from him through their psychic link.
Eva had numerous miscarriages, but one had created a lithopaedian. Steven's influence over the years reanimated it, and its murmuring into Eva's mind eventually made her insane.
After ten years, she brought Steven to Winnie, asking her to exchange the "damaged goods" for a healthy son. The proximity of his twin caused Gabriel to draw the remaining life from Steven, killing him. This made the N-Form home in on the house they were in, and absorb Gabriel and Eva.
However, Eva's insanity overwhelmed the N-Form and it went on a rampage through the Quadrant. The Seventh Doctor was able to get the N-Form to fully revitalize the lithopaedian. It tore its way out of Eva, killing her. (PROSE: Damaged Goods, AUDIO: Damaged Goods)