Terminus weapon drop rate.

Sooooo back to this game after a year away. Got an npc party that can actually run bahamut, but got it down to like 8 minutes, not to had, better than nothing

Have ran it like 15 times, still no weapon drops. Did anyone ever figure out the drop rate for these dang things? Should I still hold off on unlocking all the characters, or was that debunked? My main still doest have his, nor my off main.

I want to get at least my mains before I go into the last 2 fights that I haven't even attempted yet

Or am I just incredibly unlucky?