Thia is a synthetic android and the twin sister of Tessa who is more serious and militant focused on Wayland-Yutani's Corporations goals than she is.

Thia and Tessa were created as research synths after the re-emergence of the Weyland-Yutani Corporation, and were part of a new generation of synthetics.

Thia has spent most of her life in a laboratory and was part of the workforce at a Weyland-Yutani Corporation colony on the alien death planet called Genna one of the expedition's primary goals was to capture the Kalisk, an apex predator for biological weapons purposes.

She and her twin sister along with a handful of other synthetics spent two years on Genna. One day, Thia managed to get Tessa to agree to take her on an expedition. The Kalisk attacked the group of synthetics, leaving her one of only two survivors and with only her upper torso intact after separating her lower body forcefully from her waist, (Thia is unaware that her sister Tessa also survived).

Thia and her twin sister Tessa were designed to look like young human women with fair skin, blue eyes, and mid length light blonde hair.