Cluelessly searching for words II

Below is a word search puzzle presented without clues. Instead, you must use the additional rules (see example below) to work out what the words are. Finally, as a check to make sure you found the right words, the first letters of each word can be rearranged to make one last, related word.

This is a second, harder puzzle. See here for the easier first puzzle.

Rules

• The words can run in any direction (orthogonal or diagonal) and do not have to be in straight lines


• Words do not overlap and their paths do not cross


• All letters are part of some word


• All words are of the same length


• All words (including the final word) are related somehow


• All words (including the final word) have an English Wikipedia page, even if they are not English themselves


• The letters that make up the final word do not appear in any specific location on the grid

Example

Here's a short example.

The four words here are PONY, EMUS, TOAD and SWAN, which are all animals, and the first letter of each makes the word PETS.

Puzzle

What is the final word to be found in this grid of letters?

Hint

All the words are taken from one set of Wikipedia list pages

Answer

The full list of words is:

Domovoi
Rusalka
Amemasu
Gremlin
Orthrus

Napaeae
Sandman

As can be seen here:

With the final word being:

Dragons

All words being:

Mythical/legendary creatures