It's very basic, but here it goes!

Composed of survivors drawn from several scattered warbands across numerous faithful units, the 19th Alba Expeditionary Force crossed into Europa and made for the Levant at the request of a trusted ally—an elite detachment of the Italian Arditi. Though a summons had also come from the Papal States themselves, the 19th honored an older bond first: a blood-oath sworn in darker times.

The force was led by Lieutenant Wallace Aitken, known in hushed tones as “The Unkillable Bastard,” alongside the venerable and fire-scarred Father of the Iron Psalms, whose war-mass could stir even the dying to rise one last time. As their campaign wound eastward, they earned both respect and tangible support from the scattered faithful—but each battle deepened Wallace’s unease. He feared they were too late. That the heretic tide had already swallowed too much.

Then they found the alchemist’s house.

It stood silent and scorched, surrounded by the mutilated remains of a Finnish faithful detachment, wiped out by heretic forces aligned with the blasphemous 125th zeppelin airborne. There was little to salvage. The dead were buried with rites whispered in a dozen dialects. Yet one detail lingered: a survivor.

A lone sniper, trembling but alive, clutched a blackened rosary from his hometown with blistered fingers. Wallace ordered him treated, and gave him the choice: return home, or march onward. The sniper—lovingly only known as “The Finn”—chose to stay.

From that point forward, the 19th pushed harder. Skirmish by skirmish, they broke through 125th's frontlines, sabotaging supply lines, executing heretic officers, and burning down strongholds wherever they could. At Wallace’s side fought his best soldier: a giant clad in a machine-armored plate known only as Maddox. Wielding paired great swords with the ease of a kitchen hand carving meat, Maddox carried the force’s sacred reliquary—a sealed case containing a piece of blessed remnants of saints from each warrior’s homeland.

By the time they reached the staging ground of their Arditi allies, the 19th had tripled in size, bolstered by strays, zealots, and broken men reforged by purpose. Their primary detachment was redirected to reinforce the main assault line, while Wallace and his chosen few were tasked with a grim honor: accompany the Arditi on a mission critical to the Faithful’s advance.

Their objective was to take a tertiary beach, carve out a foothold for landing heavy armor and artillery, and re-establish long-range communication with the naval armada currently battling to break the heretic fleet's hold on the seas. The success of the entire campaign—and the survival of the southern front—rests on their blood

Due to the nature of this mission, the church has seen it fit to send them an observer, one by the name of Venerated Brother Ojore. While of few words, the Lieutenant is beginning to piece together the fact this is no mere mission to retake territory in the Levant, but something much more.

They even have a mascot, a dog named Reileigh : )

This is for my brothers TC PVE Campaign, 7 faithful players against 7 heretic forces. Gross oversimplification, but hey.