Sydney was an army brat whose father settled in at the Joint Military Training Facility outside of Los Angeles. She grew up on the beaches of Southern California and at military bases around the country. All she knew growing up were guns and the surf. Her father, Colonel Oren Diamond (1968-2035) served at several American bases before being assigned to the JMT in 2013. Her mother, Tracee Holmes (1970-2066) wrote free lance articles for gardening and new age healing websites.

Sydney did well in school, babysat neighborhood children and gave guitar lessons. When she graduated high school, she signed up for the army doing a three year tour including twelve months in Iraq before her father was able to arrange her to be reassigned stateside. While in Iraq, she was promoted to Corporal. She was in several fierce fire fights and in one instance was part of a platoon moving across open terrain that was attacked. The commanding Lieutenant and four Staff sergeants had been taking orders behind a Humvee when a rocket took out all five. Corporal Diamond assumed command of all four squads and overtook the enemy position. She earned a field commission of Sargent as a result. By the time Sargent Diamond returned stateside, she had a Medal of Honor, two Distinguished Service Crosses and four Silver Stars. She was never wounded.

Sydney was taken to the orbital platform in 2014 at age twelve and found to be a candidate for genetic modification. She was given a small augmentation giving her an initial H.E.R. of 1.379. In 2018, when it was projected that she would shortly be put in a combat position, a second augmentation was performed raising her H.E.R. to 2.067. In 2020, a third augmentation brought Sydney’s H.E.R. to 2.279 and a fourth, after her hire by the Institute brought it to 2.442.

After completing her three year commission, Sydney went to Orlando, Florida where she received an Associate of Science degree in Criminal Justice from Valencia College. She was hired by the Hoagland Institute and assigned to the security department, rapid response team one replacing one of the members lost in the Battle of Celestra Cay.

In 2031, Sydney was placed in charge of Rapid Response Team. One, and she remained in that position until 2035 when, after the collapse of the United States, she was named to the post of Security Laison to the North American Nations.  She was promoted to the Hoagland Institute's Assistant Director of Security in 2044.  She resigned from the Hoagland Institute in 2069 when the Majestic Twelve hired her to be the new director of the O.G.A.