Trash Fight
For most of the fight stack in the middle. In the 2nd and 3rd rounds, when the Mage (Incinerator) spawns, both DDs stack on the Mage and kill it while the tank and healer stay in the middle (BRP Addon Helper shows with arrows where and when exactly Mages spawn). On the 4th round 2nd wave 2 Mages spawn on the sides of the arena.

The tank taunts the left Mage and stacks with DDs on the right Mage. When the left Mage moves to the middle, tank can come back. The DDs finish the right Mage and can go back to the middle as well. The healer stays in the middle and chains the remaining adds (healer can interrupt left Mage if needed).

During all trash rounds Cleaver/DK will spawn most of the time from entrance whilst on the 4th round there will be 2 Cleavers spawning on 1st wave and 2 DKs on the last wave on the sides of the arena.

During all the arena use your ultimates to kill the DKs and Cleavers whereas on the 4th round last wave make sure not to use your ultimates so you can have it for the Boss fight.

Boss Fight
Stay in the middle in a square formation: the tank stays on exit side, the healer on entrance side, the DDs on the right and left sides close to the boss (you should make the formation at the spot where the boss spawns). Block the meteors when they appear and don't stack/stay in red (the tank doesn't need to move). If there is not enough DPS the boss should stay on its spot and start the spinning mechanic without teleportation.

Trash Fight
During most of the trash fights, stack on the exit and don't stay in netch's aoe. During the fight don't stay in the Archer's cone, don't stay too close to the adds since most of them do cleave damage (especially Crocodiles/Hoarvors), try to move around the netches. Tank should always taunt Crocodiles as they present a major threat.

Save your ultimates for big adds (Archers, Haj Mota, Troll, Wamasu). Our group used all ultimates on the 2nd round for Archer/Wamasu, one DD/Support ultimate on the 3rd round last wave for Troll/Archer, and then on the 4th round for Wamasu.

On the 1st round last wave there will be Archer spawning on the exit. On the 2nd round there will be Haj Mota spawning and right after it, the Archer on exit side. On the 3rd round every wave has a Troll spawning (remember not to stay too close to the Troll). On the last wave of that round Troll will spawn to the left side and Archer to the right side. Everyone stacks on the Troll's side so the Archer moves to the middle. When the Archer moves, stack on him with Troll and kill them. While stacking/moving keep your eyes open for Troll's stomp and netch's AoE.

On the 4th round last wave there will be Wamasu spawning on the exit and 2 Archers on the sides of the arena. Kill the Wamasu, then stack on the left Archer. Move to the right Archer when it comes to the middle. To stack the Archers, tank taunts both Archers and moves to the left Archer. When the right Archer is in the middle, move to the right side so that the left Archer comes to middle as well. Remember to watch out for netches while doing that.

Boss Fight
The boss spawns in the middle and teleports here and there. He spawns a Troll at 80% of the boss' health. Focus the Troll and move to the boss (remember to not stay close to the Troll).

Later on, a Haj Mota spawns at 60% of the boss' health. When fighting the Haj Mota, try to face it to the wall so it doesn't travel too much and kill it. Use DDs/healer ultimates on Haj Mota, but wait till the boss is away so you don't overdps the boss (if boss drops to 40% while the Haj Mota is alive, the Haj Mota will enrage). After Haj Mota is dead, move to the boss.

Wamasu spawns at 40% of the boss' health. Focus on the boss and follow him after teleport. Tank stays with Wamasu after teleport.

When Bug Bomb happens on the DDs or healer, they stay stacked and the tank keeps facing the boss/adds away. If the tank has it, use Magma Shell/Barrier and stay alone. In some situations the tank can get the mechanic twice. In that situation for the second Bug Bomb, everyone stacks on the tank and pays attention to their surroundings.

During the Boss fight, don't interrupt the Boss so that the Bleed stacks drop from the tank.

PS: It's good to have purge on the healer/tank throughout all the arena since there is a lot of deadly/purgeable dots. Don't stay too close to the adds when they do their mechanics. Troll does the stomp. The Haj Mota can kill you when it starts charging even if you're behind it and his shockwave can kill you if not blocked. The Wamasu has a deadly conal lightning attack and shoots out lightning spheres in all directions. Both Crocodiles and Hoarvors have one-shotting conal attacks.

Trash Fight
Stack on the middle and DPS. The most important task is to chain/interrupt Infusers and don't stay in red. Ultimates can be used for stacks of Infusers/Gargoyles. When Gargoyles spawn you can move to entrance so their AoE will spawn on the side and not in the middle.

On the 1st round 2nd wave 3 Infusers spawn. Try to blockcast during this fight until the Infusers are dead. During 4th round 1st wave also blockcast since 4 Infusers will spawn.

Boss Fight
Always stack in the middle. Tank needs to go to the side when the Bat Swarm counter is at about 5 seconds as the boss likes to drop Swarm quicker than what the counter indicates. Come back to the middle when it drops on the ground.

While tank is moving boss aside, the healer can chain the adds. Most Important to chain are the Infusers. Interrupt and cleave them down.

During fight, the boss can start draining a group member which needs to be interrupted ASAP. Pay attention to this mechanic since it might happen while Boss is standing in Bat Swarm.

When Colossus spawns, try to blockcast (we had situations where Colossus kept attacking people despite being taunted). Use your ultimates on it since while Colossus is up it makes the Boss invulnerable.

When you're about to get cursed, try to stay close to the portal and cleanse yourself ASAP (the boss is immune when you are cursed). After that chain all the adds from the portal.

During the fight the boss might be directed towards the group (for example when coming back from the side after casting Bat Swarm). DDs/Healer need to pay attention to boss' movements and keep their distance and also not stay in front of the boss since she's doing an AoE Heavy Attack.

Trash Fight
1st Round
Stay on exit throughout all the round. 1st wave Cleaver spawns on the exit. 2nd wave a Crocodile spawns on the exit and 2 Mages and 1 Infuser spawn on the sides.

Taunt the crocodile and chain the Infuser. The DDs interrupt the Infuser if needed. The healer focuses on range interrupting the mages. After chaining the Infuser, the tank can taunt the mages and move to the entrance corners to stack them. When the Infuser/Crocodile is dead, the DDs follow the Mages and kill them. On 3rd wave Archer spawns on the exit. Stack on it and kill it (remember the netches and Archer's cone).

2nd Round
Every wave starts after any 2 adds are dead. To make it safer we kill only big adds and leave small ones behind. When all big adds are dead, kill all the stacked small adds and last wave should proceed.

During the 1st wave the healer stays on the exit side (not to close to netch) and chains all the Archers. The tank taunts Only Cleaver and moves to the middle. The DDs stack on the left side, kill the Mage, and then move to the Cleaver. At this point kill Only Cleaver.

The 2nd wave starts when 2 adds are dead (Cleaver/Mage). On the next wave, a DK and other small adds spawn. The tank taunts the DK (that spawns on Right side of the Arena) and stacks it in the middle. The healer should keep stacking small adds on the side (again chain archers and taunt 2 small melee adds, but watch out for their heavies as they can one-shot you if not blocked). DDs focus on the DK and after it is dead, kill the rest of the adds (again, the next wave starts when 2 adds are killed). Use your ultimates while fighting Cleaver/DK.

On the 3rd wave, Boss Mage will spawn on middle and 2 Mages will spawn on the sides. The tank taunts the boss and stays in the middle. The healer taunts the 2 Mages and goes to the exit corners to stack them in the middle. DDs stay in the middle, DPS the boss and interrupt Mages if needed (Healer can call out if interrupt is needed since sometimes range interrupt fails due to Mage being behind/stacked on flame atronachs). After the Mages are stacked, the tank can taunt them. Focus the boss and cleave down the Mages (Tank can move the Boss closer to Mages if needed).

3rd Round
Stack on exit and kill the Archer (remember about the netch). After the Archer is dead, a Haj Mota will spawn on the left side. Taunt it and kill it on the exit. While fighting the Haj Mota, use one horn and try to face it towards a wall, so it doesn't move too much.

After the Haj Mota is dead, the Archer boss and Crocodiles spawn. Go to the middle, taunt everything, and use the rest of your ultimates. With enough DPS the Boss should die without teleporting and spawning a Troll. If you don't have enough DPS, keep your focus on the boss (move to him when he teleports) and after he is dead, the Troll will disappear.

4th Round
During the 1st wave, stack in the middle and chain everything. On the 2nd wave, stack on the entrance until Gargoyle's AoE spawns and then move to the middle. While waiting at the entrance, the Infuser from the exit should move to the middle. When back in the middle, chain the second Infuser from the left and cleave them. After they are stacked, use one horn and one DD ultimate.

After the Gargoyle is dead, the 3rd wave starts. On the 3rd Wave, the boss spawns in the middle, 1 Infuser spawns on the left side and 1 Cold Mage on the right side. Chain them in and focus the Boss. When Bat Swarm appears, the tank moves the Boss aside. Don't move the Boss too far to avoid getting trapped by the netches. At this point the DDs kill the Infuser and then DPS the Boss. Use your remaining ultimates after the boss is back after casting Bat Swarm. If not enough dps you will need to cleanse in portal ASAP (the boss is immune when someone has a curse). There is only one portal so keep an eye on its position. After cleansing remember to chain the adds from portal. If the Boss has low health you can skip chaining the adds from portal and moving boss aside for Bat Swarm.

Boss Fight
The tank taunts the Mage boss and moves to the Torch (it's your pin point to position your self for Archer boss Spawn). While fighting the Mage, use the tank ultimate to shorten the fight and avoid boss spinning mechanic. We used only one ultimate on the Mage since we do want to much damage on the Archer Boss -this is explained later. When the Mage hits 30% Health, the Archer boss will spawn on the right side of the tank (if tank stayed on the Torch). Taunt the Archer boss and keep focusing the Mage boss. You can cleave a little bit the Archer boss so the Wamasu can spawn (Wamasu spawns at 50% of the Archer boss' health).

After the Mage is dead, focus on the Wamasu (or focus the Archer a bit if the Wamasu has not spawned yet). When Wamasu is up, don't cleave Archer too much if possible. After Wamasu is dead, stack in the middle and chain adds if any spawned, dps the Archer with light and heavy attacks to around 42% health and wait for Bug Bomb to spawn (cause of this waiting, previous DPS on Archer boss isn't needed). He will spawn Bug Bomb on the group and then teleport. Wait for Bug Bomb to disappear and the Boss to teleport again. Reason behind waiting is to make burning Archer boss as safe as possible without having a Bug Bomb on us while nuking him and having optimal time to DPS him after the teleport.

When the Boss teleports (after doing everything as stated above) rush to him, use all your ultimates and burn him. While nuking the Archer Boss, a Haj Mota will spawn nearby at 40% of the Archer's health, and then Vamp boss in the middle at 30% of the Archer's health. The tank needs to taunt them both. The Haj Mota will disappear once the Archer boss is dead. The tank needs to keep in mind that the Archer boss is getting nuked so the Haj Mota and Vamp boss will spawn almost instantly.

After the Archer is dead, the tank stays on the side until Bat Swarm appears. Then the tank moves to the middle and DDs dps the Boss. While fighting Vamp Boss, remember about the drain and curse. You will have only one portal to cleanse in this fight so keep in mind where it's located. Boss is immune when someone has a curse so cleanse ASAP. And again, If the Boss has low health you can skip chaining the adds from portal and moving boss aside for Bat Swarm.

Trash Fight
During all trash waves, stack in the middle and chain in mages. One DD will need to destroy the totems (in our progress killing one totem per round was enough). Use ultimates when a Vengeful Revenant or a Soul of Void (black ghosts) spawn. The Vengeful Revenant creates a rune on the ground on which tank needs to stand until it disappears.

During all the trash fights, the healer can chain in the Mages while the tank taunts all adds (it helped our group). After chaining in the Mages, it's good to use reduce movement skill (Caltrops for example) and Immobilize skill to keep Mages in the middle. It's very important for them to stay in the middle so that you can keep interrupting them (a Warden's portal immobilizes the adds for a short duration after they're ported and you can precast it at Mages spawn location).

PS: During the trash fights, the most important thing is interrupting. In our group, we had a stamina DD using Vateshran dual wield to AoE Interrupt adds. Other ways to deal with it is for everyone to keep bashing all the time or a DK use Deep Breath (best on the tank).

Boss Fight
The tank stays in the middle and faces boss towards entrance. The rest of the group stays behind the Boss. Interrupt when needed. One DD needs to kill totem when it spawns.

When the ghost phase starts, the tank moves with Boss to the side/corner until the explosion timer appears. After the explosion, the boss will cast a negate field on his position. During that time rest of the group will collect "Yellow Ghosts" (remember to touch the ghost's body not just the yellow circle).

When the ghost phase starts try to stay away from each other since everyone will get DoT which will explode after 10sec dealing low dmg if you are not near the other player. To seperate group and make collecting ghosts more organized during that phase one DD collects ghosts from the right entrance rune to the left entrance rune (and uses the left entrance rune to cleanse). The healer collects ghosts from the left entrance rune to the exit rune (and uses the exit rune to cleanse). The last DD collects ghosts from the exit rune to the right entrance rune (and uses the right rune to cleanse). The DDs/healer path of collecting ghost might be changed to your preference.

Use your ultimates at the start of the boss fight and after the explosion when the boss is in the middle. During the boss fight, Boss' Clones will appear. The tank taunts them and DDs cleave them down.

The Boss and the Clones will keep jumping throughout the fight. It's very important to place the jump AoEs on the sides of the arena during the ghost phase to avoid placing the negate field close to the middle. When the Boss/Clones land from a jump, block the wave. When you are not currently doing a ghost phase, stay in the middle with the jump and move aside when the Boss/Clones are about to land (and remember to block).

PS: During the Boss fight, tank shouldn't collect any Ghosts since there won't be any rune to cleanse (on trash fights it doesn't matter).

During all the trash fights and on 3rd and 4th Arena bosses we had chain skills on both tank and healer (warden's portal) to make stacking adds faster.

In our progress run our group was using following addons:

Blackrose Prison Helper - don't need to say much here. All around help during all the arena (It seems it clashes with another addon called Samurai. So if you are using BRP Helper turn off Samurai addon).

Wizard's Wardrobe - very good addon for quickly changing setups between rounds/waves. Addons like Alpha Gear or Dressing Room didn't seem to work correctly on some of the Arenas.

NeverGonnaPickYouUp (BRP sigil synergy blocker) - addon to Block Sigils (its not needed if you are not progressing Unchained)

Bandits User Interface - very good addon to show a large amout of Combat Notifications like Heavy Attack from Footsoldiers (my personal number one reason of death). Remember to turn on this setting:

The way I look at the map (just in case someone was not sure what LEFT/RIGHT means).
Red - Left Side
Green - Right Side
Black - Exit
Blue - Entrance
Brown - Middle

PS: If there is anything what is unclear, worthy of adding (maybe I forget something what might be important) or I did some grammar mistakes. Please PM Me or leave comment. Thank You in Advance.