Raptus, the 4th boss in the Dread Palace operation does not change much from hard/veteran mode to Nightmare/Master Mode difficulty. We have more force executions to time and deal with and a newly added "spin cycle" mechanic for the long burn, otherwise if you have the hard mode version of this fight down, NiM will not take long to tackle.
Group composition does not carry to much impact on this fight for dps and heals. This is one that I believe is made exponentially easier if both tanks play as vanguards. Though any tank class can clear it, vanguards using their hold the line can completely ignore Raptus's annoying knock backs and throws. For the guide I will assume use of this dual Vanguard Tank, as it is my strategy. If your composition is different, adjustments to tanking will be needed.
The Phases/Sequences of the Encounter
Raptus is a fight that goes through repetitive phases as it progresses, the phases more revolve around the areas they are fought in. Below is an outline of the phases of this encounter:
Throne Room - The fight starts in the room we enter, but we are quickly transported.
Santuary of Nightmares - We arrive in a large arena orbited by many smaller platforms. We collect our "curses" quickly and get into position for the fight.
The Main Area begins when Raptus breaks out of his shied.
The fight in the Main Arena ends when Raptus challenges us (~ 75% HP [its on a timer])
The portal to the challenges open
Challenge Platforms - Players enter their challenges, 1 DPS is called out to stay behind and play keep away from Raptus
Challenges end and players resume the fight on the main arena
Raptus shields and curses/crystals are recollected
We Repeat the Main arena phase
We Repeat the Challenge phase
We enter "Burn", which is essentially the Main Arena phase with the addition of "Spin Cycle".
Just as in Hard mode, we begin this fight in Raptus's throne room, before being teleported to the main arena. New for NiM is the addition of Force Execution. As soon as Raptus lands in front of the tank pulling the fight he will do force Execution. I recommend pulling him and having the group stand in Force Execution, with the Vanguard Tank popping "Sonic Rebounder" to protect the raid and deal damage to Raptus, quickly pushing this phase.
This can be dangerous to party members that are not closely watching their rebounders buff. As soon as their rebounders are consumed, the need to get out, or they will die.
The main tank on Raptus should back straight up and pop a strong defensive to avoid taking excessive damage from the frontal cleave of Force Execution. (I use Infused Kolto Packs/Energy Yield to just ignore all of this damage. It is not substantial damage, but our Kolto will be back up before it is needed again.
If DPS is normal/slow Raptus will do his double cleave next. You should already have this pointed away from the group from moving back out of force execution, simply run through the boss to avoid this damage/knock back. Your team should be pushing by this point in the fight.
Main Tank pulls, Raptus immediately does Force Execution.
Main tank moves backward, dragging Raptus/Themselves out of the death zone.
Raptus does Deadly Slash soon after Execution. Raptus will not move/turn while he channels this, meaning that we can run through him to avoid the knockback and damage.
The first phase should be pushing right after this mechanic, again if your group is taking advantage of rebounders and does well with DPS, you will likely not even see this first Deadly Slash.
The Main Arena
Just as in Story and Hard Mode, we are teleported to The Sanctuary of "Nightmares" to face off against Raptus's exceptional one liners and challenges.
Time is shorter to get your crystal before Raptus awakens. I recommend popping movement enhancements and gap closing to Raptus to get in quickly.
Same crystal (Curse) assignments as in Hard Mode, Tanks get purple, DPS get Orange and healers get Green.
"Main Arena Phase"
The main part of this encounter takes place in the larger platform of the Sanctuary of Nightmares. In hardmode this portion of the fight is pretty much a dummy parse fight with some knockback mechanics (which do not start until the second round of the main floor phase.) Nightmare mode kicks us right off into every telegraphed attack Raptus has in his arsenal. Good coordination between your tanks is the key to the main floor sections of the fight. Ideally Raptus should stay fairly stationary, only moving a few meters to the other tank after a force execution. If you find it to be a scramble across the entire platform and your DPS are chasing the boss around, your tanks are likely eating the knockbacks from deadly slash, or are not taunting as outlined below.
Tanking this boss is the real challenge to clearing this fight. DPS and Heal mechanics are nearly identical to Hard Mode, with the only added challenge being the need to move out of more force executions.
My coTank/Team sets Raptus up in what I call the "T" formation. We position ourselves as tanks on either side of the Square Tile below The throne area. Raptus stays in that square with the Melee DPS between Raptus and the throne. Ranged and Healers typically stay right in front of the throne on the raised platform.
This positioning is the goal, we move around much more in NiM Mode vs Hard mode due to the increased force executions forcing us out of this pocket. Always try to reset to this formation.
Knowing the Telegraphs
Force execution comes out very early into the fight in NiM (not until burn in HM). When running timers, or being able to predict when executes are coming, I prefer to move Raptus off of the center "square" so that my cotank can taunt him and pull him back into position. If it goes out in the center of the field, adjust until it is over then reset him to the center.
I let my cotank take Raptus when the battle resumes in the Sanctuary of Nightmares, if they are a Vanguard/PT tank they can rebound when the execute channel starts to protect the Melee and provide extra dps. Right as the channel ends, I taunt back. There seems to be a threat drop at work after each force execution. If a tank does not taunt right after execute he can jump to a random party member.
Deadly Slashes can be avoided, run through the boss when this mechanic comes out. If you see your cotank get knocked back from this, taunt immediately. Raptus will jump to them, if not moving the boss to the edge (a very dangerous place to be). If reaction is slow, run out to your cotank and taunt him back, he will leap to you, escort him back to his square. It is not a great idea to leave your cotank stranded that close to the ledge with Raptus on him. If rising thrust comes out (the mechanic that launches the tank high into the air), they are a goner.
"Force Wave" - not channeled attack against Raptus's active target. This will chase the Raptus's Target and cannot be avoided. It does relatively low damage and does not knock the player back.
"Deadly Slash" a channeled ability that the tank should avoid by running through the boss. Other players caught unaware will be knocked back if they stay in this. It is good form for the tanks to keep this mechanic aimed away from the group. This will throw you nearly half the length of the battlefield and can easily throw a player into the void (more often than not rendering them un-battle revivable).
"Force Execution" - NiM sees a huge step up in the number of times that Raptus uses this mechanic. Any players caught in the circle will by the end of the channel. The lightning burst being shot out of the front and back (toward the tank and 180 degrees from them) deal massive damage and should be avoided. The active tank on Raptus when this is going off needs to take care to back straight up to keep the conals of this attack aimed away from the group and predicable for the rest of the group to move out of. The conal will follow the tank, so attempting to move toward the left or right will swing it around possibly killing players. Having the off tank taunt during this channel can also radically swing the conal around killing players. I find this mechanic best dealt with by having the active tank back straight up and pop their strongest defensive cool down. The off tank waits until the channel ends, then taunts, bringing Raptus back toward the center of the room.
Your Challenges Await
When Raptus reaches around 75% (the challenges opening are on a timer, your group may be north or south of this HP percentage), the challenge doors will open. 1 of your DPS will be called to face raptus. Everyone else will head in. We let the tanks go in first, so they can get back out first to take Raptus.
The Tank challenge, the trick here is to lose as little HP as possible. In NiM the tank closest to the add will take more damage. My CoTank and I bounce back and forth sharing this as much as possible to level out the damage. We usually take turns burning our quick recharge defensives and keep up our offensive abilities that generate shielding/defense, like energy blast, or warding strike for example. Great place for the shield adrenal. Save your best defensives. I've never seen the tank challenge failed, it's pretty easy imo, be sure to play it off as the hardest thing you've done. Makes us tanks look extra important ;).
The DPS challenge difficulty is increased in NiM mode. The adds will now have a shield that bounces back and forth. DPS the one without a shield, then swap when the shield swaps. The DPS check is tight, and easy to fail. Failing the DPS check provides Raptus a 10% damage increase (which is much of an issue).
There is now a Debuff that healers need to cleanse themselves of when they enter their challenge. It is reducing outgoing heals by 99%. Failing the Heal check will make Raptus reflect 10% of incoming damage back to the attacker. (more of an issue)
Failing any challenge will take away DPS uptime from the boss after the challenges is over.
Back to the Main Arena
The rest of the team will be rejoining the "challenged player" who should be playing keep away from Raptus while everyone else was busy with their challenge. The "challenged" player should be trying to kite Raptus closeish to the tank portal so that they can taunt when they get back from their challenge.
If all challenges were passed, combat with Raptus will resume with him immediately doing Driving Thrust on his target. I recommend doing a double taunt when picking him back up, as he seems to threat drop after the first taunt wears off and can jump to any party member and kill them with driving thrust.
Driving Thrust - Much like Tyran's thundering blast, this attack however is not a beam attack and only hits Raptus's active target for a massive amount of damage. This seems to come out right after the challenges finish.
Whichever tank ends up taunting second, pops a very strong defensive for Driving Thrust. It will hit a tank for ~250k. We are usually 60% HP after challenges, so this attack has the potential to kill us. My cotank and I run our energy shields or battle readiness immediately after stepping out of the challenge door. Raptus will reset to the center stage and reset for curse collection quickly, so avoid using things like hold the line, or too many defensives/offensive cool downs.
If a challenge fails, there will be no way to DPS Raptus after exiting the portals. Raptus will stay in his spin attack until he resets at the throne for curse collection. Tanks can taunt and bait him back and forth between them to keep him off of other players. He cannot be damaged during this phase.
Reset to The Main Arena Phase (Rinse and Repeat!)
The exact process begins again from the top. Now tanks will be seeing more instances of Rising thrust to deal with.
Rising Thrust - Launches Raptus's active target high into the air in an arc. If the player was close and pointed toward a ledge, will likely end up with the player off the cliff and dead (unrevivable). This dangerous and annoying mechanic is primarily why I choose 2 vanguard/PT tanks for this fight. Between 2 vanguards we can maintain our hold the lines up for 80% of our tanking time on the boss. We routinely tank swap not for mechanics, but when our hold the line is down and the other tank's have refreshed.
In addition to this, same as hard mode, the "wash cycle begins". Wash cycle (called the "swirly by most) will target a random player and can be the cotank. After a short few seconds the affected player and anyone inside of the graphic are washed away to the end of the broken bridge and forced to run back into the engagement. Though temping as the off tank, avoid using hold the line to get back faster, unless it is an absolute emergency. Hold the line is a very strong defensive for ignoring mechanics in this fight. Save it for that use.
Challenge will open next and repeat the exact same as the first run of this encounter.
Raptus should be around 40% HP after finishing the second round of challenges. Upon exiting the challenges, it is a great idea to attempt to recollect your curse crystals. The off tank can run up and collect theirs and during the tank swap the other tank can get theirs back.
The new mechanic here is "spin cycle". During what I call spin cycle, Raptus will go CRAZY fast sniping about (invulnerable to damage). He is easily 300% faster than we are. He will select a target and begin chasing them, he will then quickly swap targets, then swap targets again, then fixate on a player and chase them for an extended duration, this player will need use of some form of major movement boost (transcendence, hold the line, blade blitz or a friendly pool) to escape death. He will switch to one final target before the channel ends. The general strategy to survive this is for all players to spread out around the ring. If you are the chosen player, start running further way, everyone else can start to head even further to the other end of the arena.
As soon as Spin Cycle ends, a force execution is coming (very soon)
Burn is a sequence of dealing with these spin cycle phases until you kill him. Keep vigilant on the mechanics and it is an easy W.