Terribly evil nun excited about one German's revelation (9)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

Anagram (terribly / exciting) of EVIL NUN around I (one in Roman numerals), then G (abbreviation for German). I can’t see why we need both “terribly” and “exciting” to indicate the anagram; it doesn’t work as two separate anagrams, because then “about” is needed to put UNN around VEIL and can’t also work as the containment indicator for I. Any ideas?