Patch 6.2 removed The Steps of Faith and converted the encounter with Vishap into a solo instanced duty. The duty is vastly different from the trial, but it's still much longer than most solo duties done at this point in the game. The fight essentially functions as a long DPS race, but now ends at the Third and last Ward. Each ward will have a Barrier Strength Gauge; when at 0, the ward will break.
First Ward
When the duty begins, Lucia the Radiant, Y'shtola, and Thancred will be fighting at your side alongside numerous other NPCs against Vishap's horde. Approach Vishap to begin the duty, and he will summon many dragon adds. Vishap remains untargettable, so focus your attention on the adds. While you are fighting them, Vishap will cast twice Flame Breath, an initially untelegraphed AoE down the middle, to weaken the First Ward. Get out of the middle or risk taking massive damage.
Soon, a Horde Armored Dragon will appear, but has no noteable abilities other than a damaging Dragon Stomp. Once it is defeated, Vishap stuns everyone and prepares Cauterize, an extremely long line AoE that kills anyone caught in it. Once the stun wears off, follow your allies as they retreat in front of the First Ward. Once that is done, a knockback AoE appears to indicate Vishap landing and becoming targettable for the first time. The abilities he uses here are:
Fireball: A purple marker will appear on every single NPC to indicate Vishap launching fireballs on everyone. Make sure you do not overlap with anyone to minimize damage.
Body Slam: A knockback AoE that is at the same time being cast with Fireball, now a bunch of AoE circles on the ground. Make sure you are not standing in front of any AoEs before the knockback occurs.
Sidewise Slice: Vishap will rear his head forward and slice it around the arena. Get underneath Vishap or huddle against the Ward to get out of range of Vishap's bashing head.
Eventually, Vishap will use Flame Breath to completely destroy the First Ward, beginning the next phase.
Second Ward
When Vishap becomes untargettable and he and the Horde charge ahead, that's the cue to retreat. Vishap will be launching untelegraphed fireballs, Blazing Fireballs at the party in random locations as they retreat. Thancred and Y'shtola will stay to hold back Vishap while you and Lucia retreat to the Second Ward to protect it, where Yda and Papalymo are also helping. This add wave ends with a Horde Transcendent, which Yda will kill with a Limit Break. Vishap then returns to the arena, indicated by a knockback. Abilities in the first phase are retained, but new ones are present as well.
Earth Shaker: A frontal cone AoE. Move to the left or right walls to avoid being hit.
Earthrising: This will be the first time players will ever encounter this kind of mechanic, consisting of two Exaflares. Exaflares are red circles with yellow arrows that indicate numerous untelegraphed circle AoEs going ahead in a straight line, so don't be in front of them when they cast.
Flame Breath: Just like in the first phase, Vishap uses this to destroy the first ward, forcing Lucia to order a retreat to the next and final Ward.
Third Ward
Once again, watch out for Blazing Fireballs as you retreat and let Yda and Papalymo hold back Vishap while you help Estinien Wyrmblood and the other defenders keep the Horde away from the Final Ward. Watch out for AoE circles caused by the untargettable Vishap casting Fireball. Once the adds are defeated, Vishap returns to the battlefield for the last time, beginning the party's last stand. He retains the mechanics from the previous two encounters, and severely weakens the final ward with Flame Breath before showing new mechanics.
Earth Shaker: This now spawns three cone AoEs that cover the entire arena. Go the spot where the AoE covered the ground last and stay there until the other two are cast to reveal a safe spot.
Scorching Breath: Vishap prepares a final attack to destroy the last barrier; however, Lucia and her knights form a shield and take the brunt of Vishap's relentless flames to protect the Ward. A Knights' Resolve gauge will appear to indicate how long the player has before Lucia and her knights are killed; defeat Vishap before the gauge reaches 0 and the duty will be over.
As the remnants of the Dravanian Horde take to the skies in disarray, Ishgard's weary defenders breathe a sigh of relief. The siege is ended. Speak with Alphinaud at the Gates of Judgement and find out how your allies fared in the battle at the Steel Vigil.
Moments after greeting Alphinaud, you are joined by a grateful Ser Aymeric, who humbly thanks you for your service. When the lord commander subsequently takes his leave, Alphinaud triumphantly declares that the stage has been set for Ishgard's return to the Eorzean Alliance. Make your way back to Revenant's Toll, and report your success to Minfilia.
Minfilia greets your return with a mixture of triumph and relief. Having snuffed out the Dravanian threat, it is time to enjoy a well-earned rest.
Ere you commit yourself to the siege, you should know what it is you are tasked with defending. Beyond the Gates of Judgement lie the Steps of Faith─a great bridge of stone that leads directly to the city of Ishgard.
More than simply a means to cross the Sea of Clouds, the bridge serves as a foundation for the arcane wards that form the barrier we call Daniffen's Collar.
Alas, in dispelling the barrier's outermost layer, that thrice-damned witch Iceheart stripped the bridge of its protection, and thus are the dragons now able to land unhindered upon the Steps of Faith.
Should the Dravanians succeed in destroying the remainder of the wards, the winged devils will be free to swarm within the city itself.
Needless to say, we cannot suffer that to happen. It shall be our task as defenders to prevent any harm from coming to those parts of the bridge wherein the wards are sealed.
Three yet remain, and we have dispatched our forces accordingly. I would ask you and your comrades to accompany our defenders at the outermost ward.
One of Nidhogg's greatest champions...slain. The Horde will not soon recover from this blow.
But what of you, Nidhogg? Why did you not join your minions and make of this battle a slaughter? Have you grown so fond of the stench of your lair?
Mayhap you prefer to have your allies fight your battles for you... You have a girl to do your bidding now, do you not? No matter. I shall slay Iceheart, and all the rest...
...But I yearn to spill the blood of a great wyrm, Nidhogg, and only your death will sate my lance.
By the Fury... You have driven the Horde from the Steps of Faith! You! A stranger to our land! I confess, I did not think you capable of such a feat...
Yet you yielded not an ilm in the face of dragons that would turn my brother knights' blood to ice. The Fury Herself must walk at your side!
Nay, I'll not deny it: without your skill and fortitude, the city would now be ash. Would that more of your adventuring brethren possessed such qualities.
You have served us well, adventurer─the Temple Knights would have been hard-pressed indeed to turn back the Horde alone. Mayhap 'tis time I returned to the practice yard...
'Tis a rare opportunity to find onself confronted with so terrible a foe. Rarer still to emerge victorious. I should hope we need not contend with more of Nidhogg's champions.
Commander Leveilleur, Forename... True to your word, you arrived to aid us in our hour of need.
On behalf of the Holy See and the people of Ishgard, I offer you my humble thanks.
Though I would stay and lavish you with well-deserved praise, I fear I must away to oversee the aftermath of the siege. Not all the dragons are fled, and there are yet wounded to be carried from the field. Pray let us meet anon that I might express my thanks with the proper courtesy.
We have indeed achieved a victory of singular importance.
With the Dravanian Horde thus weakened and scattered, the threat to Ishgard has been greatly diminished.
And, mayhap equally significant, the Holy See must now recognize the necessity of cooperation with foreign powers.
Long have they barred their gates against the outside world, but I am confident that the day will soon come when Ishgard proclaims itself a member of the Eorzean Alliance once more.
Much have we sacrificed in our struggles against dragons and primals, the Ascians and the Empire. But, step by unfaltering step, we march ever nearer to our goal.
And, as ever, the journey is made with you in the van.
The victory you have won this day gives us greater hope for the morrow.
'Tis a hope that shall sustain us in the days to come, and bear us past the many evils that yet seek to hinder our progress. Yes, we have done well, my friend, and I, for one, would take a moment to savor the enormity of our achievement!
...The demands of duty, however, allow me little time for levity. I must accompany Captain Ilberd back to Ul'dah, and reassign those Braves whose squads suffered heavy losses.
You, my friend, have earned a rest at the Rising Stones. Pray return to Revenant's Toll, and share your tale with Minfilia in person.