'y' is a vowel in each of the "words with no vowels." It can be a vowel or a consonant.

K is correct. It's not a vowel in a word like 'year', in which it's pronounced like a Germanic 'j', but 'sky' is pronounced /skai/, and there's simply no way to argue that that is a word without a vowel (the same goes for the rest of the words as well).

I also wanted to point out that Y is a vowel in these cases—I put "y as vowel" as the link, in fact. Also, I put "Tolkien" as the link between elf, man, dwarf, and ent and felt that it should have counted, but oh well.

All valid criticisms, even though I got the "y" group sorted (and not as the leftover)...

I did want to give credit for accepting "LOTR" as a keyword, which is well done, though I do agree "Tolkien" should work as well.