The Human-Reaper was an incomplete Reaper being constructed by the Collectors. Under the orders of Harbinger, the Collectors began abducting humans from colonies across the edge of the Terminus Systems, taking them to the Collector base.
Once at the base, the abductees were stored in organic pods. Periodically, they would be broken down into raw genetic material which was pumped through tubes to the centre of the Collector base and used to construct the Human-Reaper. EDI suggested that the Collectors were 'facilitating Reaper reproduction' by constructing a new Reaper, and also estimated that the Collectors would have to gather millions of humans in order to complete it. EDI also speculated that any Reaper is built to resemble the race used to create it, and that the Reapers had unsuccessfully attempted to construct a Reaper from Prothean raw material.
When Commander Shepard discovered the Human-Reaper, it was an inactive larva, supported by four tubes. These tubes funneled genetic material into the Reaper and also served as supports. After Shepard's squad destroyed all four tubes, the Human-Reaper fell into a pit to its apparent destruction. However, it was able to activate itself and climb back up to engage Shepard and the team. They proceeded to destroy the Human-Reaper once and for all by damaging specific points on its armour.
The Human-Reaper slams the battlefield with its limbs, occasionally tearing away a platform. If standing near the edge when this occurs, Shepard may be knocked off the platform and killed. The Human-Reaper also possesses an energy weapon fired out of its mouth. This weapon requires a charge-up time, signified by distinct visual and sound cues, and will damage any Collectors in its path.
The Human-Reaper cannot be destroyed through conventional means. It possesses a number of 'Weak Spots' in its armor that must be attacked in order to defeat the Human-Reaper.
At least on normal mode, the fight against the Human-Reaper is fairly simple. Keep to cover when it is out. The Infiltrator's and Engineer's Incinerate power or a biotic's Warp are particularly effective when fully leveled, as are sniper rifles. However, it is not easy to hit it with powers when Human-Reaper quickly changes its position, so it would be wise to wait until Human-Reaper stops for its charge-up attack. While other heavy weapons are effective, the constant exposure from the Collector Particle Beam deals significant amount of damage. As long as you keep to the center of platforms and in full 180 degree cover from it, there is a high chance of winning with little difficulty.
The M-920 Cain is capable of taking a huge chunk out of the Human-Reaper's armor bar, although this is difficult and is at best a gamble. The charging time on the weapon means that you'll be exposed to any incoming fire, and the fact that the Human-Reaper moves around further adds to the difficulty. If brought, it is best used early in the fight when the Human-Reaper is moving around a lot less.
Note: Killing Harbinger when he appears causes him to drop power cells that refill ammo for all of Shepard's weapons, including heavy weapons.
- During development, the Human-Reaper was nicknamed "Baby" .