A few notes on this setting
Sin & Grace is set in a far distant future where space travel is common and humanity has pushed out from our own solar system in several exocolonial waves referred to as 'Expansion Rings.' In doing so, they have met other space faring species and alien contact has become normal in this cosmopolitan future. The current expansion is the fourth expansion, commonly referred to as the New Frontier and is notably more successful than the third expansion, called the Spinward Fringe, which pushed out towards the spinward edge of the galaxy.
Synthetic Intelligences have achieved legal personhood in human controlled space, but there is currently no wide spread developer of such intelligences. They spontaneously emerge from the source code of more limited virtual intelligences. The whys and hows of this phenomenon are still something of a mystery, but a true synthetic intelligence that can integrate comfortably with organic life is in high demand throughout the settled galaxy.
Human augmentation is common in the spacelanes. Even relatively unaltered humans like Grace will have implants that give them seamless access to the Feed, which is how they refer to the galactic communications and information network that is the future's answer to the Internet. Some humans, such as Sin, will opt for more intense augmentation in order to serve the needs of their career.
A note on pronouns:
Xe/Xer/Xir: Gender and species neutral pronouns. These pronouns are most often used when speaking about a stranger whose gender or species might be in question, or about an unknown person. Some individuals will also use these pronouns as an all-purpose replacement if they don’t want to bother learning more than one set or if the common trade language doesn’t have an acceptable equivalent to the way they refer to themselves in their native tongue.
Personal is Xe, plural is Xer, Possessive is Xir.
Basically, these are the pronouns you use if you don't know, don't care, or are scared to get it wrong. The allen wrench of pronouns.