Ha I've never heard of the Nemesis Killer of X thing. That's cool.
Bounties are the meat of Adventure Mode. Upon starting a game, there will be 5 bounties in each Act. Once you complete all 5 bounties in an Act, talk to Tyrial and he will hive you a Horadric Cache. That's what I'm referring to when I use the work Cache. Also note that some legendary items (including the almighty RoRG) can only be found in these caches. Thus they are referred to as Cache Only legendaries.
I found both of my RoRGs solo, so it is certainly possible. You can get it much much faster doing split bounties in a party.
What you mention is part of a Rift, Adventure Mode, or a Greater Rift? Can it be achieved solo, which is the most likely way I am going to try.
Bounties are the meat of Adventure Mode. Upon starting a game, there will be 5 bounties in each Act. Once you complete all 5 bounties in an Act, talk to Tyrial and he will hive you a Horadric Cache. That's what I'm referring to when I use the work Cache. Also note that some legendary items (including the almighty RoRG) can only be found in these caches. Thus they are referred to as Cache Only legendaries.
I found both of my RoRGs solo, so it is certainly possible. You can get it much much faster doing split bounties in a party.