In order to get to Samarog you will need to unlock the gate to in front of his Arena. This can either be done by a thief or by collecting 4 pieces of rubble. (Map of Rubble). The piece next to the gate requires you to have already picked up a piece of rubble.
Samarog selects the fixated player based on range, which resets every 10% into the fight, which means that you will need to discuss with your squad who will be tanking. Typically, Samarog will be tanked by both Chronomancers.
You will also need to talk about who will deal with pushes in the splitphase.
As you run in to engage Samarog, the first person to run in will gain Fixation. It is recommended to run it all at once and stay behind him, bar the fixated person. Samarog's first attack will be a Prisoner Sweep.
Prisoner Sweep is the first mechanic that you will encounter. Samarog can knockback your squad into the spikes surrounding the arena unless you block/dodge it or already are standing behind him. If you do not have 2 stacks of Stability or a block you should dodge Prisoner Sweep to avoid the Knockback and heavy damage.
After the first Prisoner Sweep Samarog will alternate between Claw, Prisoner Sweep and Shockwave until 90% of his health has been reached. Claw only affects people standing in front of him, Shockwave affects the whole group. (Gif of Shockwave) To avoid Shockwave you can just jump over it if you are not fixated, or dodge it. As Shockwave is unblockable, the Fixation can either dodge or move before jumping. During the channel of Shockwave, Samarog does not move.
(Gif of Brutalize) After 90% of his health has been reached and every 10% after that Samarog will use Brutalize, jumping onto the Fixated player and gaining Fanatical Resilience as well as a 4,500 breakbar. At this time Samarog is effectively invulnerable so you should ignore dps and try to break the bar as quickly as possible. The target of Brutalize can be healed and will take constant damage. The Brutalized player will be defeated if his healthbar reaches 0. All other incoming damage like Spear Impact will still affect the brutalized player.
During this fight with Samarog, spears will also spawn in a pattern around the Arena. These can be cleared either by damaging them or using SOFT CC. The most common tanking spot avoids overlap with spears and should be used. (Picture/Gif of Spear spawning patterns, with Tanking spot marker)
Once Samarog reaches 66% he will go invulnerable and charge into the cove opposite of the entrance to the Arena, lethally trampling players along the way.
Guldhem and Rigom will spawn once Samarog reaches the cove.
(Map of G/R Spawn + stacking spot)
Guldhem uses a cleaving autoattack as well as Anguished Bolt, an AoE stun. Rigom uses an autoattack as well as Anguished Wail if he gets killed.
To complete this splitphase you need to remove a damage negating shield from Guldhem, which requires you to have the AoE of Anguished Wail to be on Samarog.
It is recommend that you stack in front and middle of the cove.
As soon as Samarog enters his Splitphase, move into the stacking position in front of the Cove. Rigom and Guldhem will both fixate a player and move towards them.
As soon as Rigom reaches the satcking position he should be CC'd into Samarog's hitbox. Once Rigom has been moved under Samarog it is recommended to use an Immobilize skill such as to keep him locked in place. It's worth mentioning that Guldhem's stolen skill, Throw Magnetic Bomb, can also be used to keep Rigom in place in a pinch.
Once Rigom is in place you should attack Guldhem. He will not take any damage; but Classic Misdirection will pass on all damage and conditions to Rigom. Once Rigom's health reaches 0% he will use Anguished Wail. If that hits Samarog, Guldhem's shield will be removed and he can be damaged. The Shield reappears at 66% and 33%. After Guldhem has been killed you will need to pull Rigom out or (let him walk out) and kill him to finish the Splitphase.
During the splitphase a Spear of Aggression can spawn on your stacking location. If that happens sidestep its spawning location and soft CC or kill it, then move back.
Once the Splitphase has been dealt with Samarog will become vulnerable again and walk out of the cove. As before, the furthest player will gain fixation, and Samarog will start of the second phase with a Prisoner Sweep. The only additional mechanic you will have to deal with is Inevitable Betrayal.
Inevitable Betrayal targets two players. One will gain a huge Green AoE around them, the other a smaller Orange one. Once the Green AoE fills out it will deal a massive amount of damage to all friendly players standing inside of it. The Orange AoE has no negative effect towards friendly players.
To deal with this the players targeted by Inevitable Betrayal need to move out the mainstack, and stack on top of each other. The Orange AoE grants a shield to both targeted people, negating the damage you receive from Inevitable Betrayal
You should never move in front of Samarog when you gain Inevitable Betrayal as Prisoner Sweep can still hit you, and knockback you far away from the group, making it difficult to revive you.
Deal with Inevitable Betrayal accordingly, otherwise complete this phase as before.
The second splitphase is nearly the same as the first; Inevitable Betrayal is active here too.
If you get stunned by Guldhem’s Anguished Bolt while you have Inevitable Betrayal do not panic. Stand on the same spot and quickly move out - the duration of the stun is shorter than the time Inevitable Betrayal needs to explode
The third and final phase has exactly the same mechanics as the first two phases, with the only addition being Bludgeon. Immediately after the second splitphase Samarog will use Bludgeon before moving out of the cove.
Bludgeon only hits in front of Samarog and can be blocked, or sidestepped the same way Prisoner Sweep and Shockwave can.
After a Bludgeon attack, there may be an attack where all of the spears in the arena will fly towards Samarog, damaging players if they get hit by them.
Complete this phase as you completed the first two.