DC comics have always been darker than Marvel comics. When you start a comic and a kids parents are killed in front of him, I consider that dark. My favourite comic series of all time must be Knightfall, when Bane breaks Batman's back and how he is healed and trains with Lady Shiva to get back only having to face Azrael, who beat Bane. Another favourite is the Injustice series. Now that was REALLY DARK.