Regenerators are special Necromorphs that appear in Dead Space 3. They bear a significant resemblance to the Hunter and Ubermorph, and share the same regenerating abilities. From various logs and game clues, it is implied that the Regenerators are the former members of the Deep Dig team on Tau Volantis.
In basic body shape, the Regenerators resemble the Hunter more closely than the Ubermorph. However, they maintain the same smooth skin as the Ubermorph's, although they have large gashes in their abdomens and appears to have Unitology markings upon their bodies, suggesting that they may have been former members of the Deep Dig team, which logs state that when they had no surface to scrawl Marker symbols on, they would use their own flesh. The Witness RIG, which was confirmed to be the suit worn by the Deep Dig team, is covered with the exact same symbols as the Regenerators sport on their flesh, further backing up this hypothesis.
The Regenerators were created sometime during the S.C.A.F. expedition to Tau Volantis, when the members of the Deep Dig team were digging into the surface of Tau Volantis. They were attacked and killed by Necromorphs. Their bodies were soon found, mutated into Regenerators and they were contained in small transfer boxes and delivered to the CMS Terra Nova and some warehouses on Tau Volantis. But the Scenario Five order was initiated and the captured Regenerators were left to be undisturbed on Tau Volantis.
Two hundred years later, Isaac Clarke and Sgt. John Carver cleared the cargo on the Terra Nova's tram tracks, accidentally letting loose the Regenerators on the ship. When they reach the Terra Nova's cargo hold, the first of these creatures freed itself from its tube, initiating a chase. Not long after the first encounter, a second Regenerator comes out of a vent and also gives chase to the duo. They reach the tram station and activate the tram's services, but until it arrives, they fend off the assault of the Regenerators and their allies. Even at the Aft station, the Regenerators still gave chase, especially after Ellie accidentally began the launching procedures and knew no way to undo the action. As the Crozier proceeds to launch out of the station, hordes of various Necromorphs and Regenerators appeared and attacked Isaac and Carver in their attempts to end the launch sequence. The duo finally go into the engine room, and find explosives jarred in the gears. They make use of the auto cannons set in place there and begin unjarring the gears. As they do so, the Regenerators, along with Slashers as backup, make their final attempt at killing them. The beasts meet their ends at the hands of the auto-cannons, however, and Isaac and Carver unjammed the gears, and were sucked out into the vacuum of space, directly under the tram's road.
On Tau Volantis, Isaac encounters the Regenerators in the Marker Containment areas underneath Tau Volantis. They appear to be locked in their boxes, but more appear from the ventilation ducts and attack Isaac and Carver. When Isaac reaches the small room containing the Suit Kiosk, Bench and an elevator, three Regenerators appear and chase Isaac and Carver in a gauntlet run until they both escape and return to the underbelly of Tau Volantis.