Harvesters received their name due to their primary criminal activity being to "harvest" augmentations from others. Either scavenging them from dead bodies, or violently removing them from still living victims, before attaching them onto themselves or selling them on the black market.
In 2027, The Harvesters have their own compound, a repurposed parking garage in Youzhao District. This compound is where mechanical augmentations are "harvested" from victims. Their boss, Tong Si Hung, also owns The Hive, a nightclub which he uses as a front for the gang and as his personal office.
Common Harvesters have cheap, occasionally mismatched, scavenged mechanical augmentations, and wield pistols, machine pistols, combat rifles, and shotguns. There are also heavy Harvesters who wield heavy rifles. These Harvesters are distinguished by their full welding helmets and slow movement speed. Some Harvesters also have Glass-Shield Cloaking Systems and will activate them in combat.
In 2027, Harvesters are a minor enemy faction encountered in Hengsha. Lead by Tong Si Hung, the Harvesters act as gang security in many of the lower-income parts of the city. Besides mugging unwitting victims and stripping them of their augments, they have a forced and shaky alliance with Belltower Associates. They dispose of the bodies of any augmented people murdered by Belltower, in trade for getting to harvest the augments from them. Belltower manages to hold this alliance by keeping Tong Si Hung's son, Tracer Tong, hostage. The bartender of The Hive, Bobby Bao, runs a shylock scam; where they sell expensive augments to desperate people and force regular, costly payments under threat of violently taking the augments back. They have also been hired by Diamond Chan to kidnap and forcefully augment prostitutes who refused to be augmented willingly, in order to make them dependent on him for neuropozyne and bring in higher paying clients.
They are encountered by Adam Jensen during his first trip to Hengsha. Jensen eventually confronts their leader in his dance club, looking for the where about of Arie Van Bruggen. Tong eventually discloses that they are hiding Van Bruggen, from Tai Yong Medical and Belltower, in the Alice Garden Pods. Belltower eventually finds Van Bruggen, killing all residents of the hotel, including the Harvester guards. Van Bruggen, with the help of Jensen, manages to escape both Belltower and the Harvesters.
One of their shylock scams is shutdown when Bobby Bao hires Jensen to try and shakedown a woman named Jaya, who they had sold a CASIE augmentation. Jensen is informed of the scam when he confronts her about it, before returning and making Bao agree to leave Jaya alone. The Harvester's operation with Diamond Chan is also disrupted. On request of Mei Suen, Jensen frees a prostitute named, Ning Tsai, who they kidnapped, before either killing Chan or having him arrested.
Jensen encounters them again upon his return to Hengsha, having learned that the GPL implant of one of the scientists he is searching for, Dr. Sevchenko, had been detected in Harvester territory. Jensen successfully infiltrates the Harvester's compound and confronts Tong once again. Tong, now wearing Sevchenko's augmented arm, informs Jensen that Sevchenko had been killed by Belltower and delivered to them for disposal. 
Jensen and Tong make a deal: in trade for Tong telling Jensen where the body was shipped from and helping him reach the location, Jensen rescues his son and helps him escape Hengsha. Jensen agrees and frees Tracer from a team of Belltower Spec Ops. Tong then has his men smuggle explosives into Hengsha's harbor. Tong somehow manages to hack Jensen's Infolink channel. He sends Jensen to retrieve the explosives and blow up the port's manager's office, in order to create a large enough distraction for Tracer to reach his personal boat and escape. Tong also has his men set a very short time limit on the bomb, presumably in an attempt to kill Jensen. The bomb explodes, Tracer escapes, but Jensen survives to continue his search.
Harvesters come in two varieties. Regular and Heavy troops.
Regular Troops make up the bulk of the Harvester's ranks. While heavily augmented, they do not have specialize augments and can be neutralized as easily as any other opponent. They are armed with Zenith 10MM pistols, Widowmaker TX shotguns, and FR-27 Sanction Flechette rifles.
Heavy Troops are much rarer, only 4 residing in the Harvester's hide out. They are much tougher than their common counterparts and much more heavily armed. They are equipped with M404 Heavy Rifles.
- Faridah Malik's body can be found in the "chop shop" room of their hideout, if Jensen failed to save her during Belltower's ambush on the 2nd visit to Hengsha.
- During the 1st visit to Hengsha, the Harvesters will make thinly veiled threats to Jensen, implying their desire to strip him of his augments.
- During the second visit, all Harvesters in and around their hideout are hostile and will shoot Jensen on sight. That is until Jensen makes it to their surgical room and strikes his deal with Tong. After this, they are generally friendly toward Jensen, complimenting him on being so heavily augmented with such high quality augs.
- Several Harvesters can be seen reacting in pain when the Illuminati start causing mass biochip glitches.
- Jensen can overhear some mentioning that their cyberlimbs had been acting up when trying to rip the augments off someone else, allowing their prey to escape.
- Many Harvesters have eye-shields, similar to Jensen's, but theirs do not seem to be able to retract.
- It is never stated why Tong tried to kill Jensen, even after he saved his son, but it can be inferred to be revenge for Jensen shutting down so many of the Harvester's operations in Hengsha.
- The Harvesters's headquarters was originally intended to be in Bangalore, India, with the second trip to Hengsha intended to be a trip to India. Difficulties in implementing this lead to the developers folding that content into Hengsha instead, allowing for more development of Tong as a character.
- The Harvesters run an underground fight club. The developers intended this to feature a larger role in the story and with the possibility of participating in the fights, but it was decided not to fully implement it. The fight club narrative exists through the "Fight Night" email on Bobby Bao's computer in The Hive and in a secret room in the basement of the club where someone who ran afoul of the gang and the fight club has been tortured and murdered.