The Sontarans are a highly militaristic race in the Doctor Who universe.
Individual Sontarans are hairless humanoids with three digited hands standing about 1.25 meters tall with a robust build. Sontarans are native to a heavy gravity world and as such are stronger than a human physically. Sontarans reproduce artificially, cloning large numbers of additional Sontarans for their war machine. Despite that genetic variation does exist among the Sontarans. While they have mouths, Sontarans feed through a hole on the back of their neck. Striking this hole even lightly can disorient them.
Sontaran society is militaristic in the extreme. While they do not have the single-minded belief of absolute superiority that the Daleks have nor their drive to exterminate all other forms of life, everything about their society is geared to total war. Sontarans do have a code of martial honor.
The primary foe of the Sontaran Empire is the Rutan Hegemony.
Sontarans possess advanced energy weapons, starships, and teleportation technology sufficient to move troops from orbit to a planet's surface. They can also deploy specialized technology against known threats, such as a device that disables firearms. They do not appear to possess time travel technology, which limits their threat potential in the Doctor Who universe.
In addition to cloning more Sontarans, they can make clones of other species for use as infiltrators. Infiltration clones depend on a remote connection to the original tissue donor for access to knowledge and memory, and they will die in a few minutes if the connection is broken.
The Sontarans are a major galactic civilization in the Doctor Who universe. Their ability to rapidly produce replacement troops makes them exceptionally dangerous in a war of attrition.