Clues for the word "ARCHFOE"

We've had 3 crossword clues used for this word, and seen it 3 times in crosswords. It was last seen in Penny Dell Sunday crossword on November 20, 2016.

Referring Clues

Lex Luthor, to Superman
Horace set about female - his main opponent?
Chief enemy in vault with iron ring inside

Last Seen In

Penny Dell Sunday - November 20, 2016
Guardian Cryptic - September 26, 2013
Guardian Cryptic - October 24, 2005