Source: Dr. Who
Location: As a space faring race they can be found most anywhere. Currently they are natives of a parallel dimension.
Threat Assessment: 7.5. They are highly armored, super strong cyborgs armed with advance weapondry. They like to attack in numbers and to capture humans for "upgrades." They know no fear.
Limitations: They believe in their own superiority. They used to be vulnerable to gold dust. Newer versions can be taken out with EMP weapons. Also, they are repressing all human emotions. Being freed of that can leave them in a dangerous mental state.