Sheila was a maiden in 1300 AD who first hated the time displaced Ash Williams and then fell in love with him. A Deadite possessed her for a short time, became possessed by a Deadite and turned into "Bad Sheila". Upon the defeat of Evil Ash and the Army of Darkness, she was freed of the Deadite and witnessed Ash's return back home to his own time.
Another version married Ash Williams who decided to stay in 1300 AD. This version had lost her right hand, and battled Deadites alongside her husband. Pregnant with his child, they married. Unfortunately during the reception party, a drunken Ash spoke the words "Klaatu Barada Nikto" which sent him to 1350 AD.
In another reality, after Ash returned to his time, she was convinced by the Wise Man and Lord Arthur to help them create a team to continue the teachings of the Promised One. She became a teacher to what would eventually become the 21st century's Supernatural Military-Adjacent Response Team (S.M.A.R.T.).
Another version would be involved in his adventures, both in the early 14th century and in his own time. She would travel to the future and back, multiple times. Fighting alongside him against the forces of the Necronomicon, ending up trapped in the Mirror Dimension, for a time becoming Evil Sheila again, and helped Ash fight the Four Horsemen of the Apocalypse. The two of them went back one last time to 1300 AD and were going to get married. Only for Ash to call it off when the Wise Man told him she was destined to die if she stayed with him. Left in the care of her newly resurrected brother, Ash took a potion that put him to sleep for 7 centuries.