vET Asylum Sanctorium
Offtanking the vAS+2 fight will require a high level of awareness of the fight and an understanding of the timers that rule the mechanics/timing of the three bosses. Once you do, the fight becomes much easier.
The main priority of the offtank is to make sure the mini bosses Felms and Llothis are stacked on Olms or at least moved to positions where the group needs them to be. Understanding how the timers work and how they may overlap with one another is crucial to moving Llothis or Felms at the right times (such as when one is jumping and the other is about to port, your next decision will affect the group's DPS).
Other than stacking the mini bosses and acting as a sort of composer for the orchestra that is vAS+2, the offtank needs to communicate and work well with the team's interrupter so that Llothis doesn't kill the group with Oppressive Bolts. Highly recommend that the offtanks run a destruction staff (preferably Lightning) to use Crushing Shock if an interrupter cannot get to Llothis.
There are, of course, other things a tank (Dragonknight or Templar) must/can do for the group. Regardless of whether you are running a buff set like Spell Power Cure or if you're running a selfish set, it is highly recommended you still run Crusher enchantment on one bar. Weakening enchantment and Minor Maim will be needed to help with reducing the damage done to the group, specifically with Llothis' Defiling Blast.
As the person who is also taking the same punishment as the DPS do (Defiling Blast, Felms' AOEs/bacon lines, Olms turning around occasionally, Storm of the Heavens), you'll get to see the entirety of the fight and how it needs to flow for the group to succeed.
The main tank in the vAS+2 fight represents an epitome of tanking in the Elder Scrolls Online. While many people only understand this particular role to just be taunt Olms "and block forever," they also do not realize that - just like every other role in the fight - there are numerous methods/tricks to help alleviate the fight's stresses to help the group succeed.
As a Dragonknight main tank (others have done it on Templar main tank and a couple of other classes, but Dragonknight is more or less the most ideal), you must be keeping up debuffs as best as you can on Olms, including Engulfing Flames, Crusher (Weakening if need be), Minor Maim, Linebreaker (Alkosh) & the standard Major Breach/Major Fracture with your taunt.
In addition to this, you mustn't move Olms closer to the wall unnecessarily nor should you be too comfortable taking too much damage from Olms right before or during Storm of the Heavens. This helps your healer both survive and do their job. Furthermore, it is of high priority that the main tank keeps Olms' eyes away from the left or right side where the DPS are, as Exhaustive Charges can stray over to where they are, which can make the +2 fight much more difficult.
As the main tank, you are not only responsible for your own survival but the survival of others close to you. Healing Orbs (in conjunction with Earthgore), Aggressive Horn and Efficient Purge are highly recommended for this final but equally important aspect of your role.
The "Back Healer" or group healer is another part of the puzzle that is the vAS+2 fight. You are primarily in this role to keep Felms' maim AOEs (unpurgeable 50% damage reduction) out of the group as he jumps up to three times from the furthest person relative to his last position then to the furthest person from that point on, etc.
The Back Healer should always be aware of the timer on Felms' jumps. When there's approximately 3 seconds left, they should either be in position or run to the back of the room in order to draw Felms' aggro.
It is highly recommended that you have at least 24k health in order to survive both the expected and unexpected outgoing damage of this fight (including an Olms jump, enraged Felm AOEs, Llothis Defiling Blast and so forth).
Always make sure to purge yourself after the maim. Ideally, back healer should also provide resources, heals, and purges when possible to the DPS. Resources can be supplied via shards, orbs, and elemental drain (Warden healing is viable in this trial). Because of how dynamic the fight is, top sources of healing are Mutagen, Healing Springs/Illustrious Healing, and Breath of Life. Abilities such as Combat Prayer are not as viable, especially given the time spent outside of group (another factor is group composition, particularly Magblades that don't need Minor Berserk anyway).
Back Healer should try to provide a purge when possible after Olms' Fire on Execute. If possible, leaving an Extended Ritual in the group will help DPS survive. The Back Healer should also be running Aggressive Warhorn as their main ultimate and use it whenever possible in the main group, as they are one of two support able to hit all DPS. The Restoration Staff Ultimate should be saved for moments of excessive need, such as Felms having two or more stacks of enrage.
If trying to survive enraged Felms' mechanics, all it requires is awareness and timing. A Back Healer in all light can survive one stack of enrage by shielding before Felms jump and walking out of it. Two stacks or more, however, you'll need to pay a lot more attention to those AOEs and subsequent bacon lines that erupt out of them.
The "Tank Healer" is another important part of the vAS+2 fight and definitely is an adrenaline rush when you first do it. Like the "Back Healer," the Tank Healer is there to keep Felms' Maim AOEs off everyone else. In this case, off of the main tank that's in front of you. In addition to dealing with the maim AOEs that put a heavy bleed on you or the main tank, your other job is to attract Olms' Exhaustive Charges (the lightning pools) so that they don't drop on the main tank.
It is very important that the main tank doesn't get the Exhaustive Charges, so you must remain behind whoever is holding Olms or within eyesight of Olms. The lightning pools dropped will deplete resources and pretty much kill you if you remain in it for longer than a second. The Tank Healer must be careful that they don't trap themselves when getting both Exhaustive Charges and Felms' maim AOEs.
Stacking the AOEs next to one another is best. For the Felms AOEs, you can shield and simply walk or sprint out of them. For lightning pools, the healer must either dodge roll or sprint out of them as soon as possible!
It is highly recommended the Tank Healer always purge after being hit by a pool/AOE. Olms' steam breaths can be deadly if you're not paying attention or if the main tank has had to move Olms out of position, which may have the steam breath closer to the walls. The difference between a good and bad Tank Healer can be obviously seen when you're looking at where they have their camera focused. The best tank healers always have their PoV focused on Olms rather than on the floor or towards the U-shaped wall.
The best group set for a tank healer to run for this fight is Infallible Aether to keep up Minor Vulnerability on Olms and this in turns provides a nice magicka return if need be with heavy attacks. The Maelstrom Restoration Staff is also very nice for the magicka return as you're already using Mutagen/Rapid Regen.
Other than debuffing Olms, the Tank Healer should have Elemental Drain on Olms as well to provide magicka return and try to get both of these debuffs on either the mini bosses or spawning Protector Spheres when available. It is important that you still heal your main tank and provide resources. The main heals you will give to the closest DPS or the main tank will be Mutagen/Rapid Regen or Breath Of Life.
Aggressive Horn is definitely an option but the use of this ultimate from the Tank Healer for the group should be considered a "treat" rather than something that is bound on rotation as you might have in other trials.
Above all else, focus on your survival as the Tank Healer. Resurrecting a tank healer is difficult for experienced groups and nigh impossible for newer groups.
Progression? One of the best things to do is run Infused Chest and Legs for Dragonguard with 3 pieces of Jewelry. Putting Tri-Glyphs on your Chest and Legs will give you more Health and Stamina to work with. Ideally, you should not have under 24k Health.
One of the best things to do is run Infused Chest and Legs for Dragonguard with 3 pieces of Jewelry. Putting Tri-Glyphs on your Chest and Legs will give you more Health and Stamina to work with! Ideally, you should not have under 24k Health. Having 24k health means you can survive Olms' jump with block and shield if you're unable to get out of the way in time.
It is possible to get Felms to jump only twice rather than three times between both the Tank and Back Healers. This requires coordination as the healers need to stand across from each other in the center of their sides. The tank healer has to carefully watch Olms, as he will sometimes drop lightning pools right before the maim. If this is the case, step either to the left or right of the center for the pool and then dodgeroll out of it towards the center. When the maim lands, move on from there. If the back healer successfully outranged Felms, he should not drop a third time.
The role of an interrupter is yet another vital piece of the vAS+2 fight that should never be underestimated.
This role allows the offtank to more freely stack both mini bosses better on Olms for maximum cleave damage while also preventing group deaths.
Ideally the interrupter should be a Magicka Sorcerer with Crushing Shock.
It is a DPS role that demands both attention to timer/mechanics and rotation to achieve relatively high DPS numbers while helping the group live.
The two most viable stamina classes (in terms of surviving and not losing too much DPS) are the Stamina Templar and the Stamina Sorcerer.
Depending on group composition/ability, you may not bring in either of the two classes. The Stamplar is notably used by many groups for the Minor Fracture/Minor Sorcery provided by the Dawn's Wrath skill "Power of the Light".
Suggested positions for stamina is closest to Olms on either Entrance or Exit (1 or 8).
You ain't in Kansas anymoar Dorothy, this fight's gonna test your ability to DPS under extreme duress. If you fail to pay attention to mechanics, make a mistake that will kill others or don't do so hot at positioning yourself before the timers of certain mechanics go off, then time to disband the group.
You'll need to experience the fight in a consistent group if possible as kiting next to one another and then changing it up can be rather tedious until you synergize with your team.
Lastly, you should always keep DoTs or at least Blockade on stacked bosses while going for Protector Spheres otherwise you lose too much DPS.
Alternative setup: Mechanical Acuity+Master Architect
OLMS JUMPS AT 90%, 75%, 50% & 25%
During fire phase, there's no need to panic and try to move out of one fire AOE (which may affect Defiling Blast placement). There's also no need to get hit by more than one fire AOE as well.
Only one side "entrance" or "exit" will get one fire bomb at a time. It's better to always take a hit on the edge of one AOE as being too close to the fire bombs' impact point will one-shot you. Blocking/Shielding is recommended until the fire dot is gone.
vAS Timer Addon:
Lothis: (Enrage After 3min)
GREEN 22s Poison Cone
ORANGE Interrupt 12-18s
WHITE (Teleport) 25 -30s
Felms: (Enrage After 3min)
WHITE (Teleport) every 20s after final teleport, active while walking back
Storm (Olms): PURPLE 35s (can call early 30s)
Protector: A sphere can stay up for 1 minute and 30 seconds until a 2nd one spawns that tethers to Felms or Llothis.
Maim: Counts down how long you are maimed for by Felms "bacon lines" or AOEs.
The timer doesn't appear until you're in battle.
The two main timers DPS need to watch are the poison cone timer and the storm of heavens timer. This will allow for better positioning/kiting.
Also make sure to glance at timers if Llothis or Felms need to be enraged. A good rule of thumb is to always focus Felms at 2:00 on his timer if he wasn't cleaved well below 40-55%. Llothis is much easier to focus and there isn't a real need to focus him too much.