Chem was foaled in 1047 to Cherie and Chester. She is the sister of Chet. Her talent is map projection which allows her to project a map of any part of Xanth. The map's details are based on how much of the area Chem has seen.
Chem gave part of her soul to MareImbrium in exchange for a ride out of the Dream Realm. She got it back later, but released it again to release Imbri.
Chem met Xap, a hippogryph, while helping Irene search for Ivy in 1072. She mated with him, and Chex was foaled in 1073.