I spell my name Viktor, the standard Swedish spelling (cf. for example Viktor Rydberg).
In the Anglo-American world the “k”-spelling raises some eyebrows. It has even been suggested to me that the “k”-spelling feels more sinister and that in literature “k” is a letter most suited for the name of an antagonist.
The reason for this is perhaps an association of k-spellings with Russian names. This would explain such association for the name Viktor in particular. However, it seems that many Victor antagonists actually use the c-spelling, such as for instance Victor Maitland in Beverly Hills Cop. A simple search at Villains Wikia suggests a ratio of Victors to Viktors of about 7:1. Thus it seems that if the Cold War is the cause of bad-guy association for the name Viktor, it is the name itself that has gotten a bad rep, not the k-spelling specifically.
To investigate the matter further I decided to test the hypothesis that “k” is a bad guy letter statistically. To do this I needed a list of villain names. I made this list by aggregating these three lists:
http://www.superherodb.com/characters/ [“bad” filter]
As a control for comparison I used this neutral list of names:
The results were as follows. The relative frequency of the letter “k” in the control list was 0.0104913, and in the villain list 0.0129413. So indeed the hypothesis is confirmed: the letter “k” occurs about 23% more often in villain names than general names.
I wasn’t sure whether the hypothesis should concern absolute occurrences of k’s or only the frequency of k’s relative to c’s. So I also checked this. In the general list there were precisely (!) half as many k’s as c’s, while in the villain list the proportion of k’s relative to c’s is 0.569061, so indeed this form of the hypothesis is also confirmed.
But of course you can always prove anything you want with statistics. Let’s say that I wanted to prove the opposite of the above for example. Easy, I just have to get the list of superhero names from
http://www.superherodb.com/characters/ [“good” filter]
and I will find that the relative frequency of k is 0.0187919, way higher than in the previous two lists. In this way I could just as well conclude that “k” is a good guy letter after all.