I was playing in hell today and when I killed the Summoner I had an odd drop! He dropped a key of hate. I have never seen this drop before. Is this something new after the last patch? And what is it for? I play RRM/RWM and I play solo exclusively
They were added to unlock the "Uber Tristram" quest on battle.net. You need 3 keys of each type (Terror, Hate, and Destruction) and cube them in Act 5 hell one set a time. Then you can fight Lilith, Duriel, and Izual again who drop organs you can then cube to fight Uber Diablo, Baal, and Mephisto.