Conversation so far:
What is most notable aspect of Avenged Sevenfold's affinity for concept albums?
Johnny Christ stated in an Ultimate Guitar interview about the writing process of Nightmare: We wanted to have a dark concept record, sort of like The Wall or Operation: Mindcrime“
What inspired Avenged Sevenfold's dark concept record?
On December 28, 2009, Avenged Sevenfold's drummer James The Rev Sullivan was found dead at his home at the age of 28.

Question: what was interesting during this period?
Self-contained rewrite: what was interesting during the Death of The Rev and Nightmare period for Avenged Sevenfold?