I wasn't thinking about villains, only a "Oh, look, someone let a lot of vowels here ! Let's take them !" ^^
I can give you the only word I know without any vowel : crwth. (Welsh playing music, somewhere ?)
Cwrw is also Welsh, it's the word for beer.
Both of your choices of random Welsh words to know somehow surprise me not at all
(although "crwth" is so hardly used I had to google it to be sure of the meaning - extra points for obscurity go to Mélusine ^_^)
(Also, same thing as Rollo said, we've actually got way more vowels than English as we consider both y and w to be vowels as well. Can't say much about Czech seeing as I know next to nothing about it, but it looks like it would be great fun to try out
My imagination is currently setting it up as something like Dwarvish actually
)