Klingon

The Klingons (Klingonese: tlhIngan) were an humanoid warrior species that originated from the planet Qo'noS. One of the major powers of the galaxy, their government was called the Klingon Empire and the Klingon Empire. 

Physiology
The most distinctive feature of the Klingon race (except for those affected by the Augment Virus) was a cranial ridge that normally began from the forehead and often continued through the skull. 

Klingons were more resistant to alcohol than humans or Romulans. As such, they could drink bloodwine or Romulan ale without being intoxicated like these races could be.

Klingons could become zombies if they were infected with the Mijanou Syndrome.

Culture
Honor was central to Klingon society; as such, Klingons held on to their honor at any cost. For this reason, military life was seen as a path to glory, especially exceptional acts of bravery. In addition, rituals were an important element of Klingon life. Tradition was very important and a breach in tradition brought shame to the offender's name for several generations. 

Klingons didn't think very highly of science or medicine; Klingon dentistry or medical science was not as developed as it was in the Federation or the Romulans.

Klingons usually didn't value comfort; most other species, like the Lyrans, Malachorians, humans as well as Romulans, regarded Klingon facilities as being spartan compared to their own. Likewise, the Klingons regarded most other species as being too cozy.

Technology
They were known to be warp-capable and they were also capable of using weapons such as the disruptor, the photon torpedo, the plasma torpedo and their ships were capable of using deflector shields and, sometimes, cloaking devices.