It has to be a heavy if you look in the exotic heavy page there are tow unknown one is A Thousand Voices and there i one more. Everyone is saying Thunderlord and bungie did not say that it wasnt thunderlord which is a fact. So if it wasnt thunderlord why havent they posted on twitter to tell us it is not thunderlord. look on reddit, that one leaker Anon whatever his username also leaked all of the forsaken stuff and now thunderlord plus some Black armory stuff. It is pretty solid evidence