Welcome to the final boss -- aka Atheon 2.0. As is the norm with Destiny raid bosses, this one builds on almost all the mechanics that have been featured in the raid to this point. Your goal is to power up two pillars on either side of the arena, and then chain energy from those pillars to the boss to trigger damage phases. How you get there.. well that’s a bit of a mess. This is the strategy that worked for our group after a lot of trial and error and failure, but I know there are different ones and other groups do things differently. Also, if I mention something that I don’t explain, assume it’ll come up later as a lot of these mechanics tie together (and hopefully I did not forget anything..).
The boss is standing in the distance in a sea of Vex milk. You’re given an island to stand on that is split in half(sorta..) with a light side on the left and a dark side on the right. Each side has a Vex conflux with a cube on top which, when shot, tether people with energy, same as they have done throughout the raid. The island is also essentially broken into twelve sections with each section having one of those cross receptacles scattered just off the island. There are also two areas on the far left and far right that people can travel to throughout the fight.
The boss is a large Vex Minotaur-esque enemy. They won't be active at first, but it has these two large crit spots, one on its shoulder and one on its leg. If you destroy one, there will be four things that happen. It will create a portal on that side which players can travel through to go to the far area corresponding to that side (the portals stay open for a little bit, but not indefinitely). It will also bring anyone currently on the corresponding far area back to the spawn behind the island (left crit brings back left person, right brings back right). Third, it will spawn a Cyclops on an elevated platform (to the far right on the dark side and to the boss’ left on the light side). Finally, the boss will steal one of the sections of your island. The section will glow red for a few seconds and then vanish, killing anyone still standing on it.
If the boss takes a section, you can shoot the cube above one of the confluxes and tether the energy from that to a nearby cross to get the section back. Like the previous encounters, you can’t do much while tethered, so wait till adds are gone to do this. It is important to get the middle sections back, but less so for some of the back and far side sections. That said, whenever you don’t have adds, I recommend trying to get a section back because even if it isn’t one you use, it could be one the boss takes instead of a more important one later on.
When players go to the far areas, there will be two types of enemies, either Harpies or Goblins. When you kill enemies, they drop motes which can be collected and deposited when back in the main area. Players can only hold ten motes and there will be a total of fifteen motes dropped if the enemies are Goblins and eighteen if the enemies are Harpies. Depositing motes into the confluxes gives the enlightened buff which, like before, is needed to break shields on shielded Goblins which are trying to sacrifice themselves to the confluxes. If there are sacrifices, it will drain motes and eventually cause a wipe. That said, you cannot allow any Vex to sacrifice as this strategy does not really leave you any extra time to collect more motes. When you’ve deposited thirty motes in one of the confluxes, you’ll get a message that the conflux pulses with energy which indicates that conflux is done. The shielded enemies will stop spawning on that side as well, although there might be some stragglers that need to be dealt with.
You want to break up into two sides, a left side group (light side) and a right side group (dark side). Within each side, you then want to assign people to three different roles, team 1, team 2, and defenders. At the start of the fight, an Angelic will be up, so kill that to activate the spots on the boss. When the spots come up, shoot the shoulder one immediately to activate the first portal. Both team 1 members go through the portal to collect motes. The two defenders are responsible for killing the Cyclops as soon as it spawns as it can easily kill people. Once team 1 has all the motes (either fifteen or eighteen), they say pull us back, and the group shoots the shoulder target again. This brings team 1 back and opens the portal which team 2 goes through. This also creates another Cyclops, so the defenders need to immediately take it down again. Team 1 deposits their motes to both gain the enlightened buff. They then defend the confluxes on their respective sides from the shielded Goblins that will be trying to sacrifice. Once the second team has collected their motes, they call it out and are brought back. The defenders take out the final right-side Cyclops immediately. Team 2 deposits their motes which, if everything was done correctly, finishes that conflux. Once any straggling shielded Goblins are dead, the team 2 person on the right can shift their focus to helping defend the left side.
When team 2 is brought back, team 1 needs to shoot the leg crit to open the left portal to go to the other side. The defenders again need to take out the Cyclops that spawns, this time on the left side, immediately. Team 1 kills the adds on the left area, collects the motes, and then calls out to be brought back. The group shoots the leg crit again which opens the portal for team 2 to go through, brings team 1 back, and spawns a second Cyclops on the left side for the defenders to kill as soon as possible. Team 2 then collects motes and calls out when they’re ready to be brought back. The team shoots the crit spot one last time, bringing team 2 back and spawning the final Cyclops that needs to be killed. During all this, the people staying back need to be paying attention to the plates that are being taken and coordinate with their partner to try to get those back whenever there is a break in the action as needed.
If you’ve done things correctly and gotten the message that the second conflux is full, you’re good to go. Filling both confluxes triggers a second Angelic to spawn, but it also spawns after a set amount of time has passed, and the timing of this strategy is somewhat tight. I don't know if this is intentional or not, but we seemed to have issues with mechanics if the Angelic spawned before we finished the second conflux, so something to be aware of. In any case, kill the Angelic and any adds and the boss will then make a giant glowing cross/diamond thing that will be either blue and white for the light side or orange and black for the dark side. The matching side needs to tether the energy from their conflux to the cross-thing. You can usually do this with three, but if the conflux is far away, you might need four, so be aware of that and plan accordingly. If you don’t get this first tether off in time, it will trigger a wipe, although you do have a fair bit of time from when the symbol appears and when the wipe occurs. I strongly recommend assigning positions in advance when it comes to tethering so there are no surprises (so person 1 is next to the conflux, person 2 is in the middle, and person 3 is the one that connects to the boss). If you tether correctly, it will stagger the boss and open up a crit spot. You can damage it now, but make sure adds are dead first. After a few seconds, the boss will jump into the air, which makes its crit spot easier to hit, and create a second target that the side that did not tether first needs to tether their conflux to (so if the light side tethered first, the dark side needs to tether second). The boss’ crit spot is still up, so the group that already tethered should continue doing damage during this. If you tethered it correctly the second time, you’ll be given an additional twenty seconds to do damage, otherwise you just lose out on damage. Again, the boss starts on the ground before rising into the air where its crit spot is easier to hit (so save your Celestial shots for this point). I strongly recommend that the second group not worry about damage and instead spend the first part of the damage phase getting in position for the second stagger. I also recommend you wait till after the second stagger to group up as you don't want extra people being too close and messing up the tether. After the damage phase is up, everything more or less resets (the only major difference is that the confluxes can move to different positions) and you’re given a little time before adds start spawning, so use that to try to get any missing platforms back. I believe you get four cycles before the boss enrages. Do enough damage and you beat the boss, get to drop down into a hole that needs more explanation, and get loot.