I have completed both dungeons on the PTS and am currently working on a guide and walkthrough for all players struggling with any of the mechanics.
Brought to you by the guild Twin-Moons Covenant
See
Depths of Malatar Guide
Frostvault Guide
Add Priority: Skysplitter
Skysplitters are goblin ice mages, and they're main threat comes from an ice comet ability that they will cast on a random player. Kill them as quickly as possible to reduce the amount of ice comets going out, and if killed quick enough the ice comet will be canceled if it spawning on one player.
First Boss
Icestalker
Icestalker is an armored frost troll boss who has many common troll abilities, including throwing a projectile and ground slam that sends out ripples through the ground in a frontal cone. Icestalker will occasionally pounce on a player, that stuns and damages everyone nearby.
Upper Punch is when he punts a player up into the air, stunning them when they land, and begins repeatedly smashing that player. Another player needs to bash the boss before he smashes the player to death. The stun is unbreakable (currently) even after Icestalker is bashed, so the healer will need to keep that player alive through the other aoe's and adds.
The boss on occasion uses a large aoe around itself that knocks back all players, stunning them briefly.
Adds spawn in a health percentage triggers, so if they become too overwhelming, begin focusing them down. Ice wraith's heavy attacks will knockback and stun a player that they hit if not blocked. Ice Spiders are not much of a threat other than additional damage. Note: Icestalker's abilities will kill the adds, so it is recommend to NOT kite any adds when they attack DPS or healers.
Second Boss
Warlord Tsogvin
Tsogvin will occasionally turn toward a player and then shield charge them. This must be blocked or dodged otherwise it will outright kill DPS and healers.
Another basic mechanic is a tether that will be placed on two random players, and the players must separate from each other to break the tether and stop the damage from hitting both players. Very similar to a Fungal Grotto II mechanic.
The boss will periodically jump into the air (he leaves a fire visual effect on the ground from where he jumped from). He'll land at a random location in the arena with a small shield on top of his health. During this mechanic, every player will have an AOE ring around them and the boss will be channeling a fire ability that will hit every player in pulses. Do NOT stack on top of another player when this mechanic is occurring. DPS must break the shield in order to stop the mechanic from occurring (very similar mechanics to vMoL first boss).
Ice tornadoes will spawn at approximately 35% (health percentage still needs confirmation) on the edge of the arena and slowly circle the arena. These are very deadly so avoid them at all cost. During this phase, the boss will still do his jump, but this time he'll always land in the center of the arena and begin channeling a blizzard storm around him. This blizzard will grow larger rather quickly, pushing the players into the path of the ice tornadoes. Simply follow the ice tornadoes to keep ahead of them until the blizzard storm is over. In addition, the boss will cast one more ice tornado on a random player, so this extra tornado has it's own path (that of the player) to add to the chaos.
Adds: The arena will have goblin archers spawn in, that can be chained in by the tank. The archers do have some powerful abilities, including Rapid Fire (the bow ultimate), which cannot be neglected. They can be cleaved down when chained in fortunately.
Vault Protector
This Centurion Boss has very simple Centurion abilities that we've already seen, such as the heavy attack, spin attack and artillery attack that we see in Darkshade Caverns I and Volenfell. The boss only has one additional mechanic which is he will protect himself from an arena mechanic with a Dome Barrier.
Tank is highly recommended to hold the boss in the center of the room for the Sear Ray Trap mechanic.
The Searing Ray Trap mechanic is by far the deadliest mechanic in this fight as they were will outright kill any player. When the fight begins, the Protector will put up a Barrier around himself when the Ray Trap is activated and all the players need to put themselves on the other side of that Barrier that the laser is being produced from. The laser can be seen in use below. It is very important to not stand within the Protector's Barrier, as that will also kill you.
Searing Ray Trap:
The Searing Ray Laser can be dodge rolled through, but this has not always worked and it is recommended to follow the mechanic. At certain health percentages, more Searing Ray Traps will activate. They activate at staggered times, allowing players time to get around the barrier as needed to survive. You will want to burn the boss down as quickly as possible, especially once all four Traps are activating in a single phase.
Adds:
Several Dwemer Spiders and Dwemer Spheres will spawn in. The Spiders will snare you, making it difficult to get behind the barrier and the Dwemer Spheres cause significant damage. They cannot be chained in but it is recommended to taunt them.
Rolling Dwemer Spheres that will not unravel will spawn in and have an aoe around them, and have the appearance of being electrified. These spheres will travel in a straight line across the room, and if a player enters the aoe around them, the sphere will explode, stunning all players nearby.
Rizzuk Bonechill and Avalanche
Rizzuk is the only boss that needs to be killed; once killed, his Frost Atronarch will be destroyed.
Avalanche has a lot of AOE abilities and needs to be the tank's primary focus. An AOE will be planted at the Atronarch's feet that will cause several ice pillars to sprout up on the edge of that AOE. This acts as an ice prison, that the tank must stay in and survive until the AOE fades. (Unknown if it's supposed to be the donut ice AOE, seen on other enemies such as Galenwe in Cloudrest.)
Rizzuk will occasionally channel an ability that will need to be bashed. If not bashed, this mechanic will start shooting every player in the arena in a rapid fire method, (same as Fang Lair HM mechanic).
Ice Meteor Shower is a mechanic where the boss will teleport to the middle of the arena now place a DoT on each player that will also slow you all down. Eventually each player will be frozen and an ice meteor will crash into each player. You must all have been sufficiently separated, otherwise the stacking impacts will kill any player that were stacked. Healer needs to make sure everyone is topped off before frozen.
Now and then an ice ball will be created by Rizzuk and follow a random player. This player will have a target underneath them. The ice ball doesn't do much damage, and it is unknown on any affects if it is dragged into another mechanic or a boss. Other players have gotten in the path, and still took similar damage.
At the entrance of the arena spawns a spinning ice storm. It's effects are unknown as my group always avoided them but it is believed to be part of one of the mechanics. Believed to cause heavy damage. More ice storms will appear as fight progresses, but they're easy to avoid.
The StoneKeeper
Rat Maze mechanics:
Skeevatron Rat Maze is introduced before the boss fight begins, giving the group a chance to experience the mechanic. You will spawn on the map above as a Skeevatron, each player at one of the arrows seen on the center of the map, with unique Skeevatron abilities. Several of these abilities affect your allies, however this is rarely needed as you all should be going your separate ways.
Charge your ultimate once you spawn into the Rat Maze by going to the electric pillar (blue dot on the map) and spamming your first ability. Follow the pulsing lights going down the path you spawned at to a Shock Conveyor, and use your ultimate on that to deactivate it. This must be completed on four separate Shock Conveyors, one for each player. It is quickest for each player to follow their own path.
The rat maze will occur twice throughout the fight.
Phase One: Unique to phase one is the Rolling Spheres from the Vault Protector fight will be spawning at the edge of the arena and slowly rolling toward the boss. These will stun anyone near them if their AOE is touched similar to the Vault Protector fight. These can be deadly during the Fire Spin attack from the Stonekeeper.
The Stonekeeper itself is invulnerable until both his Gauntlets (aka, arms) are destroyed. The tank only needs to taunt the Stonekeeper, and that will keep the aggro of both its arm. The Stonekeeper will fire a laser at the tank, and each hit will apply a stack of a DoT on the tank. The longer it takes the DPS to destroy the Gauntlets, the greater the threat is from this DoT.
Note: Another player can place themselves between the Stonekeeper and the Tank to take a shared part of the damage. And possibly take the stacking DoT's while standing between (more confirmation needed).
The Stonekeeper's right arm is the Rotary Blade Gauntlet, and its left arm is Flame Bellows Gauntlet The tank is highly recommended to AVOID the Rotary Blade Gauntlet attack; one dodge roll will avoid all its damage and the attack will be over quickly. If not avoided, it does significant damage over a short time and believed to place a bleed DoT on the tank. Tank the Flames Bellows Gauntlet as it's damage is not nearly as much of a threat.
The DPS will need to focus down the Rotary Blade Gauntlet first! Once a Gauntlet is destroyed, a Centurion will spawn in. The Tank MUST taunt this Centurion and block all its heavy attacks, and the DPS need to kill the Centurion quickly before moving onto the second Gauntlet. Once the second gauntlet is destroyed, another Centurion will spawn that needs to be focused down.
Note: Centurion heavy attack can be dodged with a dodge roll.
Fire Spin: When both Gauntlets are destroyed, the Stonekeeper will then begin to spout flames out from his arm sockets and slowly spin in a circle. The group must keep ahead of these flames! If a Centurion is alive during this attack, the Tank needs to keep taunt of it and Block or Dodge Roll all its heavy attacks. It WILL one shot you if you do not block or dodge its heavy attack. Be careful of the phase unique mechanic during this attack!
Once the boss reaches a health percentage, both arms will regenerate and 4 Skeevatrons will appear on the arena. Each player goes to one and uses a synergy to complete the Rat Maze mechanic. Blade and Flame Traps are now active so use caution when traveling through the maze. Do not attempt to go through any trap until that trap deactivates.
Hint: A player can "resurrect" another Skeevatron if a player is killed by the traps, but must be near that player in order to get them back up.
Hint: Any damage on a Skeevatron will transfer to your character, including if your dead as a Skeevatron. Revive a Skeevatron before finishing the mechanic otherwise risk reviving the player while fighting the boss.
Phase two is the most dangerous as rotary blade traps will begin activating on the arena. The rotary blade traps replace the Rolling Spheres, but are far deadlier. These traps will likely kill any DPS or Healer caught in them. If a player survives then they will have had a stacking bleed DoT place on them for each time they were hit by the rotary blade traps. There are two tracks on the arena, so it is advised to call out if you see a rotary trap spawning on the inner or outer track so the tank can adjust properly. Destroy one arm, then kill the Centurion as you did before. Then kill the second, and kill the Centurion as before.
Destroy the arms again, survive the centurions and flaming spin until once again you enter the Rat Maze. No new mechanics when entering the Rat Maze for the second time. (NOTE: Second rat maze phase was removed in one of the pre-live patches. After the first rat maze, then kill the arms and the centurions then just burn down the boss.)
Phase three has a deadly but easy to handle mechanic which is a steam gust, a conal AOE, that comes out from the Stonekeeper. While it does not do very much damage, it will knock players back that will likely result in them falling off the arena or onto one of the fire platforms that will instantly kill a player. The tank may survive a knockback, but if an ill-timed heavy attack from a Centurion follows up, then the Tank will die.
Again focus the Rotary Gauntlet first, kill the Centurion, then focus the Flame Bellows Gauntlet, then kill the Centurion. After the final Centurion is killed, burn the boss down as quickly as possible.
