Thyest or Theist: How To spell?

The word Thyest is misspelled against Theist, a noun meaning "One who believes in the existence of a God; especially, one who believes in a personal God; -- opposed to atheist."

Word contains consecutive vowels 'EI' in between alphabets th & st is misspelled as 'YE'
Wrong Spelling:  th-ye-st 
Correct Spelling:  th-ei-st 
Explore spell check of Theist to spell without errors.