Letheyn or Lethean: How To spell?
The word Letheyn is misspelled against Lethean, an adjective meaning "pertaining to Lethe; resembling in effect the water Lethe."
Lethean has vowels 'ea' together mispronounced as 'ey'Word contains consecutive vowels 'EA' in between alphabets leth & n is misspelled as 'EY'
Wrong Spelling:  leth-ey-n  Correct Spelling:  leth-ea-n 
Explore spell check of Lethean to spell without errors.