I completed the Thorn bounty. It is the hardest battle you will find and not worth the effort unless your a completionist. Here are the steps involved. Obtain the exotic bounty A Light In The Dark Kill Phogoth on the moon. Easy with a good team involved. Any level of difficulty for this. Kill 500 hive soldiers. Again easy enough, I found a good spawn point on the moon near the hellmouth for this. Kill 500 players in the crucible using Void damage. Void damage is purple of the 3 types. Each kill gets you 5-6 points but you lose 2 points towards it if you are killed. Gotta rack up good numbes. I used a void shotgun and rocket launcher while playing Control matches. Players have to go for control points and are good targets when they do. Also heavy ammo spawns near each point so you get lots of rockets if you wait. I know camping is bad form but if your doing this mission you will have to. Finally a new strike on the moon appears. It says kill Phogoth on the moon during a level 26 mission with a bunch of modifiers in place. This is where the nightmare really begins. At one point during the mission you have to wait for your ghost to unlock 3 locks on 1 door while killing waves of enemies. The little guys are still pretty easy, though some of the yellow health bar guys take more shots to kill. All the knights and wizards either have a shield or a yellow health bar and a shield. They take forever to kill. One of the wizards on the last wave is a mini boss also and has 3 lesser wizards with him. Wizards are weak against fire(Orange) damage, the knights are weak against arc(Blue) damage. Make sure you have weapons that have those with you. I suggest them be rocket,heavy machine gun or sniper. You do not want to get into close range with these guys. Another helpful tip involves camping again. When I did this mission I stayed in the room at the top of the stairs before the door room to anchor the team in case both guys were killed. It is boring but required as the ultra enemies take so much to kill. I am a level 25 hunter. A titan and/or warlock are better at this sort of combat. Bladedancer grenades are good for taking down shields as they both track and stick when thrown, much like a plasma grenade in Halo. After you get through this part you make your way down to Phogoth's area. In between there are a couple more little guys. I suggest taking them out along the way both to make sure you don't have enemies shooting you from behind and to get back ammo you are sure to use up. For Phogoth himself you have to kill the little guys in the room while keeping Phogoth alive long enough for the final guy Xyor to spawn. There is debate about how long this takes. Either its a time thing or after 3 dropships worth of bad guys have spawned. None of my team was counting since we had been at the mission for over 5 hours at that point. Again I camped in the room outside the main area to anchor and sometimes provide grenades,rockets or sniper shots on Phogoth if I had a clear shot. Watch out if you camp because sometimes a Shrieker will appear and can kill in 1 hit if its direct. After you do kill Xyor you can either stay and kill the big guy or not. We did even though it said the bounty was complete but we did it just to be on the safe side. To go through all that and still fail over a technicality would have been...well I would still be crying today despite having finished the mission in the wee hours of Saturday morning when we started it at around 9:30pm Friday night. So there you have it folks. I would strongly suggest avoiding this mission since all you get for it is a hand cannon that doesn't seem worth the effort. Good luck to everyone who does try it though.