Sheila Lawson is the biological sister of Miranda Lawson. Developed just after their father lost Oriana, she was meant to be the perfect heir to his dynasty along with her twin sister, [Lawson]. Everything, from her intelligence, physical constitution, biotic abilities, to her appearance were designed before birth to be excellent and even greater than Miranda's. Sheila also heals faster than other humans and will live two lifespans longer.
Sheila Lawson is the second and youngest of Miranda Lawson. Like her sisters, Sheila was created to carry on his dynasty. Soon after Commander Shepard helped Miranda protect Oriana, their father made his third and final attempt at an heir, this time creating twins. Sheila was just one of the twins while Mira was the other. Their father made certain to make the twins far more loyal but once Sheila discovered the existence of her other sisters, she quickly became uncontrollable.
Sheila managed to run away from her father, though Mira remained with him, and began to search for them. To make it easier to hide from her father, Sheila travelled to the Terminus Systems to hide out while she tracked down information about her sisters. Not long after arriving on Omega Sheila learned that she had a natural affinity for combat as she was attacked and managed to kill the four assailants within a matter of seconds.
She got a rush from this incident, so she joined the newly-formed human mercenary band, Phantom. As the youngest mercenary in Phantom and the youngest known mercenary in the galaxy, no one thought much of her. The underestimation of others worked in her favor and she managed to forge a reputation as the greatest Human mercenary on Omega. She helped Phantom grow from a small squad of mercenaries to a large organization. Soon after, Phantom had gained enemies on Omega, namely being Shadow Fox. The two organizations were in a three year war up until the Phantom's eventual defeat. Nearly everyone was killed, with Sheila being one of the only few exceptions. While the other survivors wanted to start a new mercenary band, Sheila disagreed and left Omega.
She started a solo career as a professional mercenary for awhile, but quickly learned of the location of one of her sisters. She learned that Oriana lived on Illium after meeting her informant, Liana Peria. Soon after arriving on Illium, Sheila discovered that Oriana had gone missing and was presumed dead. Sheila was also intercepted by Miranda Lawson, her other sister that had been investigating Oriana's disappearance. At first, Miranda attacked her stating that the last person seen with Oriana was a blond woman of similar appearance to Sheila. It became evident to Sheila that Mira was behind the disappearance of Oriana and must've been ordered by their father to track them down. Sheila and Miranda banded together to track down Mira, obviously making their way to the most likely place; their father.
After meeting their father, he claimed that their arrival was part of his plan. He had Oriana captured in order to get all of them back in the same place. He wanted Sheila to rejoin her twin and he wanted Oriana and Miranda executed to get rid of the "rejects". Mira had other plans and didn't want to share her fortune with someone who turned against her and her father. Mira challenged Sheila to a duel, and the ensuing battle caused catastrophe to the surrounding area. Miranda and Oriana managed to escape in the battle but their father was killed. The facility that the battle took place in began to collapse and the two twins were forced to escape. As Sheila escaped with Miranda and Oriana, Mira makes her way to an unknown location.
A few months later, Sheila has been able to form a tight bond with her two sisters but was still curious of her twin's whereabouts. Sheila did some searching and had discovered that Mira had begun doing business with a mysterious krogan. It would later be revealed that the same krogan was linked with multiple criminal elements and dangerous people. Though Mira previously tried to kill her, Sheila still cared about her twin sister so she began searching for her in an attempt to save her before the krogan, who was known for his ruthless nature, decided to eliminate her as he had with many others he worked with.
Sheila Lawson is faster, stronger, smarter, and more agile than the average human making her strategic ability and overall combat effectiveness far above some of the best human warriors. She also heals much faster than ordinary humans and is still 100% combat effective with a broken arm. Sheila has a natural affinity for combat, something added by her father as she was meant to inevitably hunt and kill her older sisters. She is incredibly skilled in hand-to-hand combat, mastering Shadowken and Veradas. Her marksman skills are also incredible and she is most proficient with sniper rifles and pistols. Her infiltration talents are amazing and her biotics are impressive as she has mastered many biotic talents.