In The Doctors universe he faces many an alien as he travels through time most of which are very friendly but there are others who are sinister and evil. Of the enemies The Doctor faces in his travels none are more frightening then the Daleks and the Cybermen. Both of whom instill terror in The Doctor every time he comes face to face with one. More interesting though is the reaction of the Daleks and Cybermen.
The Daleks believe themselves to be the highest and most evolved race in existence void of any feelings and bread purely for the destruction of other races. But all of what the Daleks might want you to think is not what it seems even though they say they have removed emotions there encounters with The Doctor show otherwise. The only true emotion is one of the most primal emotions fear no matter how advance they become they are still afraid.
Now let’s look at the Cybermen a less advanced race built on humans whose goal lies close by that of the Daleks, to conquer the universe. Just like the Daleks their emotions have been suppressed to try and be a more superior being. The two-significant difference between the two races is one that the Daleks are bread into their superiority complex where as the Cybermen are forced into it. With the Cybermen if the person being controlled although has a strong enough will they can overcome the programing and have free will such as in “Doomsday”. The second difference is in how they want to conquer the universe. Daleks would prefer if the entire universe were dead and the only beings left were themselves but the Cybermen would rather assimilate others into being Cybermen.
When the Cybermen and the Daleks meet for the first time in “Doomsday” the most interesting thing that I found was how the Cybermen offered to a line with the Daleks, but they refused even though if they joined forces they would have been an unstoppable force. With their two races being so similar it seems only natural that they would join forces for the common bad so to speak.
With all this talk about the Daleks and the Cybermen I almost forgot about The Doctor. In “Doomsday” one of the Cybermen comments to The Doctor about how his emotions weaken him, yet The Doctor always ends up conquers evil in the end. This idea that The Doctors emotions make him stronger is not lost though on the cult of Skaro or at least on Dalek Sec. Later in the series we find that the Daleks are now trying to become more human under the leadership of Dalek Sec to continue their race which The Doctor complements them on because they are no longer fixated on killing but more on the preservation of life until they kill Dalek Sec. This is a big shift for the Daleks they are learning that for them to be as strong as The Doctor they may need to become more like him and we see that they are not always about killing they can evolve.