Mortmon or Mortmain: How To spell?
The word Mortmon is misspelled against Mortmain, a noun meaning "Possession of lands or tenements in, or conveyance to, dead hands, or hands that cannot alienate."
Word contains consecutive vowels 'AI' in between alphabets mortm & n is misspelled as 'O'Wrong Spelling:  mortm-o-n  Correct Spelling:  mortm-ai-n 
Find more incorrect spellings of Mortmain to spell right way.