To avoid citizen adds, you can pull him into the doorway nooks to the left or right of the steps where he stands.
Cure all deterimentals. Mostly arcane but a few traumas.
Kill all adds he summons as fast as possible, they heal him VERY quickly. Unkilled arbiters are summoned. The wider zone around him you clear, the longer it will take for adds to arrive.
Defeat Grand Cruciator Typhenon wandering between ( -4, 180, -222 ) Copy/waypoint -4.12, 179.86, -221.77 and ( -52, 180, -214 ) Copy/waypoint -51.53, 179.79, -213.85 and loot the Horn of the Fallen from his body.
Cure all detriments. Mostly trauma.
Periodically he summons a wall of shields. Target and kill the shields. Typhenon is untargetable until it is down.
Periodically he summons adds. All damage done to them is done to the adds instead. He cannot take damage while they are up. Kill them when they spawn.
Use the Horn of the Fallen near ( -145, 180, -205 ) Copy/waypoint -145.00, 180.00, -205.00
Emotes "Prysmerah, Arx Patrona gathers fire and poison!" and begins casting Arx Fire. Joust to the side to avoid the knockback and breath weapon.
A glowing scale may be placed in your bag during the fight. You have to give it to an other group member by double-clicking it. If you do not do that, you will die.
THIS DID NOT HAPPEN DURING SOLO INSTANCE, Not sure if this is bogus info.*
Use the door at ( -194, 183, 0 ) Copy/waypoint -194.16, 183.22, 0.16 to enter Arx Seru. NOTE: For the Quest Shattered Dawn: Extinguish the Corrupted Light - Inside this door are Luminary Arbiters. You must complete killing all of them BEFORE you enter the next door to confront Lord Triskian Seru or you will not get the undate. The Luminary Arbiters can not be killed after he is defeated.
Kill the mobs in the entry way to open the door at ( -80, 78, 4 ) Copy/waypoint -79.54, 78.12, 4.24
Kill all an Arx Luminary to activate several a choranal anima.
Kill all the a choranal anima to open the doors at ( 26, 78, 33 ) Copy/waypoint 26.29, 78.18, 32.51 and ( 27, 78, -24 ) Copy/waypoint 26.73, 78.24, -24.47
Speak to Lord Triskian Seru at ( 128, 79, 4 ) Copy/waypoint 128.04, 79.06, 3.71 and defeat him.
Solo- and Heroic-Zone
Cure the arcane disarm
Casts Time Slide and Temporal Interference.
Charges the nearby chronosphere's, if they reach 100%, you are teleported to ( -44, 78, 4 ) Copy/waypoint -43.78, 78.12, 4.19 and the encounter resets. As soon as they are attackable, destroy them all. The "epic" mobs are scripted and don't damage you very much. If you AoE near them, they do NOT aggro.
Hint that worked for me as solo. I would fight LTS some, then click on the first mob on the right (not Automation of Time but the chrono that is directly in front of it). I would kill one, then fight LTS more. Then I would turn and kill the next chrono then fight LTS more. Chrono reappears so you need to keep repeating this cycle. I did it I think 3 maybe 4 times before LTS was dead. It is a long battle too!
Expert-Zones:
Lord Triskian Seru will at 50% Health switch into the Forth Dimension. Where he stood, there is a "crack". You have to click it to follow him (everything go to black and white if you enter the forth dimension). WARNING: In that zone you can only survive 30 seconds.
In the forth dimenson zone there are 6 "balls". If you click a ball you will come back into the normal zone. If you have clicked all balls also Lord Triskian Seru will come back. Now do the rest of the 50% to defeat him.