In the last days of the storyline of Final Fantasy XIV: Heavensward, two battles are fought east of the Black Shroud for control of Baelsar's Wall. The conflict, which is orchestrated by Ala Mhigan nationalist fanatic Ilberd Feare, leads to a reopening of the war between the Alliance and the Empire, which had stabilized in the wake of Operation Archon and the Garlean succession crisis. Under Ilberd, who takes the moniker "The Griffin", Ala Mhigan refugees posing as Alliance soldiers storm Baelsar's Wall, only to be massacred on his orders as a sacrifice to summon the primal Shinryu, which is subdued by Omega, an ancient Allagan superweapon unleashed by the Alliance.
The battles, which concludes the 3.x storyline, leads to the beginning of Final Fantasy XIV: Stormblood; players participate through running Baelsar's Wall as a 4-man dungeon and completing various solo content.
During the Garlean capture of Ala Mhigo, thousands of Hyur fled Ala Mhigo to the inner Eorzean city states. Many became refugees in Little Ala Mhigo, a camp in Southern Thanalan. Multiple times, fanatics in Little Ala Mhigo attempted to take up arms against the Empire, even attempting to summon Rhalgr as a primal, which frequently brought them in conflict with the government of Ul'dah. This conflict is, along with a struggle for control of the Carteneau Flats and the Allagan superweapon Omega buried there, are the two major causes of the Ul'dahn Revolution. To isolate the Ala Mhigans from the Alliance, Gaius van Baelsar ordered the building of a wall on the border of the Black Shroud and Gyr Abania.
At the battle on the Steps of Faith, the Warriors of Light slay the wyrm Nidhogg, and attempt to destroy his eyes, the source of his power, by casting them into the mists below the Steps of Faith, where it is believed that no mortal can survive. However, the eyes are retrieved by the Ascian Elidibus, the Emissary of Zodiark, who gifts them to Ilberd, who was one of the masterminds of the Revolution.
Against the will of the Alliance, which is attempting to hold a shaky peace rather than try to fight a losing war against the Empire, Ilberd stokes nationalist fervor in Little Ala Mhigo with an impassioned speech, raising an army of revolutionary fanatics to overthrow the Garlean occupation of Gyr Abania.
The Griffin's attack
On Ilberd's orders, the Ala Mhigan Resistance soldiers don Alliance uniforms and storm the Wall. The attack is apparently quite successful at first, as the top of Baelsar's Wall falls to the rebels in a matter of hours.
However, a would-be rebel, M'naago Rahz, leaks the plan to the Scions of the Seventh Dawn, who call an emergency meeting of the Alliance. The alliance votes to send Doman shinobi under Yugiri Mistwalker, as well as a host of usual Alliance soldiers, to hold the Black Shroud and prevent fighting from spilling over into Gridania. The Warriors of Light and other members of the Scions of the Seventh Dawn infiltrate Castrum Oriens, overrunning the Garlean garrison and arriving at the top of Baelsar's Wall, where they are met with heavy resistance by the Resistance soldiers, but are able to fight through the waves of revolutionaries and corner the Griffin, who claims that he will see the Warriors at the the far edge of fate. After a fight, the Warriors of Light defeat the Griffin.
Surrounded by the Scions, Ilberd commits suicide, just as his lieutenant Laurentius Daye, posing as a Garlean commander, seizes control of the Garlean magitek and uses it to slaughter what remains of the Resistance. Their lives, and the energy of the eyes of Nidhogg, complete the summoning ritual that Ilberd had planned the whole time: the primal Shinryu manifests above the Wall. However, Papalymo Totolymo sacrifices his life to seal Shinryu as the surviving Scions flee the Wall.
Even while bound, Shinryu is immensely powerful, and effortlessly destroys a Garlean airship flying over the Wall after the battle.
Duel over Gyr Abania
Recognizing that the seal on Shinryu is only temporary and under pressure from Nero tol Scaeva, the Alliance moves to awaken Omega, hoping that the ancient superweapon will be powerful enough to destroy Shinryu. However, Garlean forces also launch an attack on the Carteneau Flats, where Omega is buried. Fortunately, with the aid of Scaeva's magitek armor, the Red Baron, the Scions are able to take the Flats and awaken Omega. Omega immediately flies to Baelsar's Wall, as Shinryu breaks free and attacks it.
The two beings duel for an extended duration of time, unleashing a tremendous amount of energy in the skies over Gyr Abania. Eventually both are badly damaged in an explosion so brilliant it could be seen from near the Hawthorne Hut in the East Shroud, and crash-land somewhere in Gyr Abania.
Fall of the Wall
Recognizing that Ilberd's false flag operation will inevitably lead to a reprisal from the Empire against the Alliance, which they believe is responsible for the attack, Alliance forces under Flame General Raubahn Aldynn preemptively launch another assault on Baelsar's Wall. The Garlean forces, still reeling from the Resistance's raid and the devastation caused by Shinryu and Omega's battle, are ill-prepared for the attack and quickly overrun, and control of the Gyr Abanian border falls to the Alliance.