Gillian Grayson
Biological information
Born:	21 October 2170 CE Mohammed Ali Memorial Hospital, New Fukushima, Yandoa
Died:	4 February 2267 CE Shal Residence, El'Tivv, Rannoch
Physical information
Species:	Human
Gender:	Female
Height:	6.4ft
Hair:	Black
Eyes:	Blue
Political and military information
Affiliation:	Ascension program QMFV Idenna Herself
Equipment:	Omni-Tool
Era:	Asari Cycle Pax Galactica Era
Battle(s):	Quarian-Cerberus conflict Idenna incident Attack on the Idenna Reaper War Fall of Illium Citadel Siege Fall of the Citadel

"I've lost all comprehension of who I'm supposed to be, how I fit into this world. Everytime I think I've found peace, it's shaken up and pulled from me. I'm adrift. And it'll always be that way."

— Gillian to an older Lemm'Shal in 2186 CE after the Reaper War.

Gillian Grayson (known at birth as Gillian Costanzo and known to the quarians of the Idenna as Gillian'Grayson nar Idenna and later Gillian'Grayson vas Idenna) was a former Ascension program student at the Jon Grissom Academy, an honorary member of the quarian ship QMFV Idenna and part of its security force, and an intermittent vagabond. Born on Yandoa, Gillian's parents were of Italian descent, having migrated to Yandoa following the First Contact War. In 2170 CE, the year of her birth, a massive industrial accident resulted in dust form element zero contaminating a significant part of Yandoa's capital, New Fukushima, and in turn Gillian's parents was exposed: while Gillian was born without complications and would obtain the nodules necessary for developing biotics later in life, her parents were not so lucky, developing significant cancerous growths that later claimed their lives, leaving Gillian an orphan. Paul Grayson, a Cerberus operative looking for healthy biotic test subjects for Cerberus to experiment on, adopted Gillian as his daughter, but in reality was feeding her drugs to improve and speed up her biotic development: over time he grew attached to her, and persuaded the Illusive Man not to send her to the Teltin facility on Pragia. Seeing an opportunity in 2177 CE to infiltrate the Alliance's Ascension program following the catastrophic disaster at Teltin, Gillian was enrolled in the program, with Cerberus operative Jiro Toshiwa embedded undercover on Jon Grissom Academy as a doctor in order to keep feeding Gillian the medication to boost her abilities, not realizing that it was having the unintentional side effect of amplifying her autism. Born as a high-functioning autistic, Gillian was prone to social anxiety and was therefore very quiet, being highly sensitive regarding social and physical contact, but at other times bursting with sociability. Paul Grayson, being a known red sand addict, was often kept away from his daughter, by both Ascension and Cerberus alike, in order to allow Gillian to develop in a more loving environment with the former, and so as to better control Gillian with the latter. In 2184 CE, Toshiwa's latest cerebrospinal medication caused a seizure and temporary paralysis, leading to him being discovered and arrested by Hendel Mitra after saving Gillian's life, initially believing he wished to abduct her but then realizing he'd been drugging Gillian for years. Gillian went with Hendel, Kahlee Sanders and her father and fled to Omega in order to escape Cerberus, not realizing Paul was leading them straight into Cerberus' hands, where they were captured by Paul's friend and commando, Pel Ladges. Pel betrayed Cerberus and planned to sell Gillian to the Collectors, but they were rescued by quarian pilgrim Lemm'Shal, who spirited them away to the Migrant Fleet to seek refuge on the QMFV Idenna, believed to be safe.

This proved a complacency, as Paul Grayson and Pel Ladges, accompanied by a full platoon of Cerberus commandos and with a quarian exile and traitor Golo'Mekk to get them inside, used a captured Idenna shuttle as a trojan horse to board the ship and begin fighting their way through the ship to capture Gillian. When Paul managed to capture Gillian with the help of Golo, he realized how much pain he had caused Gillian and switched sides, killing Golo and helping them retreat to safety. After the Cerberus raid was repulsed, Gillian stayed on the Idenna in order to keep her safe, Hendel remaining with her and the two of them becoming integrated into the crew, gaining the honorary title of "nar Idenna". Gillian would accompany the ship on its four-year expedition, becoming part of its security force as Hendel taught her to master her biotic powers. In 2186 CE, Hendel and herself helped the crew fend off a batarian slaver attack, capturing the slaver's ship and releasing their slaves, one of which was a former Cerberus agent named Hal McCann. He informed Gillian of her father's death and, wanting vengeance, Gillian is gifted the captured slaver ship by the quarians, who also name her "vas Idenna", and leaves with Hendel and McCann to get justice for her father's death. After uncovering no leads and McCann being allowed to leave to explore a new life outside of slavery and Cerberus, Gillian is convinced by Hendel to give up her endeavor, as her father wouldn't have wanted it. Unable to contact the Idenna (as it had been recalled to the Migrant Fleet), they went to Illium, where they were present when the Reapers laid siege to the planet early in the Reaper War. Tricked onto an escape shuttle by Hendel, she was forced to watch from a window as it took off, and it would be the last time she ever saw Hendel. Taken to the refugee camp on the Citadel, Gillian would remain there, helping people wherever she could, not knowing where to go until the station was attacked by Cerberus: she would later help Sidonis' Irregulars in liberating the camp towards the end of the siege, along with many others. When the Reapers took the station in September, she was able to make it to an evacuation bunker and survived until the station's liberation at the end of the war. After a brief reunion with the crew of the Idenna on Earth, she briefly toured her parent's homeland of Italy before returning to the Citadel. Becoming a vagabond, she wandered aimlessly across the galaxy, never staying in one place for too long, not knowing what else to do. She would die in 2267 CE, over a decade after the Dominion Civil War, having concluded her journey on Rannoch, deciding that the quarians were the only family she felt she truly belonged to, and briefly stayed with Lemm'Shal's daughter, Mono'Shal, before she died one day after eating breakfast one morning, peacefully falling asleep in her chair and never waking up.