Shera (シエラ Shiera) is a non-playable character in Final Fantasy VII. She is a scientist, who once helped out when the Shinra planned the launch of the first rocket to outer space in Rocket Town. She lives with Cid Highwind, though the two are not married in Final Fantasy VII.
Shera was a scientist in charge of getting the rocket Shinra 26 into the air. However, when doing final checks before the launch, she noticed a fault in the rocket that she felt the need to fix. Then, right before launch, Cid discovered that she was still in the hold fixing the fault and was faced with a hard choice: either launch the rocket and burn her to a crisp, or abort the launch, and fail in fulfilling his dream. Not wanting to kill Shera, Cid aborted the launch.
Shera, feeling that she owes Cid for saving her life, lives with him, and handles all his constant criticism, feeling that she deserved it. In Final Fantasy VII, when Cid finally launches the rocket, he realizes that there actually was a fault with one of the oxygen tanks, leading him to forgive Shera after all these years.
In "On the Way to a Smile: Case of Barret", it is revealed that Shera has contracted Geostigma on the back of her hand. It is unknown but generally assumed that this was cured at the end of Advent Children.
In Final Fantasy VII: Advent Children, Cid has named his new Airship, the Shera, after her. As of a year later, during the Deepground/Omega Crisis, as chronicled in Dirge of Cerberus -Final Fantasy VII-, Cid has married Shera, though when this happened is not specified. If Vincent talks to Cid while on the Shera before the Midgar assault, he tells him that "Shera's been worried about you, and you know how she gets", in referencing to her overly cautious and meticulous nature.