Kasumi Goto

Kasumi Goto was widely held to be the galaxy's most enigmatic thief, a master of stealth and infiltration who had enemies everywhere yet whom few could put a name to. An expert in sabotage, extraction, and agile combat, she was recruited by Cerberus to join Commander Shepard's mission against the Collectors, and she settled aboard the Normandy SR-2 surrounded by treasures both purchased and stolen. Her own purpose was personal: to recover the stolen memories of her murdered partner. (Mass Effect 2; Mass Effect 2: Kasumi: Stolen Memory)

Keiji Okuda and Bekenstein#

Kasumi shared a deep and intimate bond with her partner Keiji Okuda, who affectionately called her "Little Bird." When Keiji proposed a heist against the smuggler and weapons dealer Donovan Hock on Bekenstein, Kasumi agreed eagerly, and the pair infiltrated the target in style, using stealth, her tactical cloak, and a decoy program Keiji had built for her. While Kasumi distracted Hock's guards, Keiji pressed ahead alone. She reached him too late, finding him dying in a pool of blood. With his last words Keiji begged her to survive and to recover his stolen graybox, a complex implant that stored his memories, so that they might be together again. Kasumi cloaked and fled, vowing to keep her word. (Mass Effect: Foundation; Mass Effect 2: Kasumi: Stolen Memory)

Recruitment and the heist#

When Cerberus tried to make contact, Kasumi noticed the approach and trailed the organization back, turning the recruitment on its head before agreeing to work for Shepard. Her condition was the recovery of Keiji's graybox from Hock. To retrieve it, she and the Commander infiltrated a gala on Bekenstein attended by the underworld's most prominent figures, then fought their way through Hock's mercenary security to reach the vault. The graybox held a secret so dangerous that, if exposed, it could have plunged the galaxy into war. (Mass Effect 2: Kasumi: Stolen Memory)

Aboard the Normandy, Kasumi made the port observation lounge her own, surrounding herself with paintings, books, and other storied effects, and would speak of her past adventures if Shepard asked. Her trained eye for observation made her one of the sharpest judges of the crew: she was the only one aboard who could tell that something was amiss if Morinth had taken the place of Samara, though she kept the suspicion to herself. (Mass Effect 2: Kasumi: Stolen Memory)

Faking her death#

Six months after surviving Shepard's assault on the Collector base, Kasumi resurfaced on the Citadel, slipping an anonymous tip to the salarian Spectre Jondum Bau, who had pursued her for years even as he respected her abilities. She quietly assisted Bau and Shepard in tracking down a hanar operative who, it emerged, had been indoctrinated by Reaper technology and meant to disable the defenses of the hanar homeworld. Kasumi stopped the sabotage, but the console was rigged and appeared to kill her in the blast. (Mass Effect 3)

If Shepard had helped her recover Keiji's graybox, she revealed afterward that the secret it held concerned a covert Alliance operation against batarians who had encountered Reaper technology, a matter that could have ignited a wider war. She emerged from hiding, having staged the explosion as the perfect way to escape Bau's pursuit, and agreed to lend her talents to the Crucible project. Where the graybox had never been recovered, she knew nothing of its contents, did not reveal herself, and stayed out of the war. (Mass Effect 3)

The final battle#

During the battle for Earth, Kasumi could be reached by hologram to report that the Crucible was ready, promising to buy Shepard drinks if the Commander survived. In the aftermath, her fate reflected her choices and Shepard's: if she had been persuaded to keep Keiji's memories, the galaxy's gathered strength was sufficient, and Shepard chose to merge organic and synthetic life, she was seen at peace holding hands with what appeared to be a projection of Keiji, the partner whose memory she had risked everything to preserve. (Mass Effect 3)