144th 'Caligari Expeditionary'

The 144th regiment to be levied by Segmentum Tempestus Militarum Command for the Indomitus Crusade, it is commonly called the Caligari Sector Expeditionary Regiment, owing to its founding troops being comprised of PDF and other loyalist forces from the Caligari Sector rather than a single planet.
The regiment is organized into two battalions, each consisting of 2 light infantry companies, an assault "pioneer" company, and a company of Tempestus Scions, along with a weapons company and battalion auxiliary units. The regiment maintains a single platoon of Leman Russ tanks and one platoon of basilisks. What little other artillery the regiment possesses consists of six towed earthshaker cannons, two heavy and two quad mortar guns.
== Service History ==
=== Roethko Campaign ===
The regiment first saw action on the planet of Roethko, a minor/developing Forge World that was embroiled in a confused series of guerrilla conflicts between Chaos cultists, pro-Tau rebels and mechanicus forces throughout its small manufactory-hives and orange-red dustbowl surface. The world belonged to a young but fierce Adeptus Mechanicus faction that forbade the 144th from deploying full companies onto its surface. The 144th deployed numerous kill team and platoon operations to thwart anti-imperial forces but met with dismal results. The situation on Roethko was greatly complicated by small contingents of Grey Knights, Ultramarines and Raven Guard astartes, each pursuing their own objectives separately and especially in the case of the Grey Knights, often directly against the 144th's operations.
The conflict on Roethko dragged on for over a year as the Tau insurgency gained a significant upper hand, scoring numerous victories against Imperial forces until a brief warp storm deposited a large asteroid nearby in the system. It was quickly discovered that the asteroid was none other than an Ork Rok, from which the greenskin menace began launching raids. While the 144th scrambled to thwart this added threat, the struggling but not defeated Chaos faction seized control of the rok's command center and managed to drive the entire asteroid into the surface of the planet with apocalyptic results, destroying the Roethko's thin atmosphere and most of its surface. None of the planet's 57 million survived, though Command did note that the threat of Roethko's manufacturing capability falling into the hands of the Tau or Chaos was effectively ended.
=== Namdec III Campaign ===
Next the 144th deployed to the nearby world of Namdec III, a civilized world of approximately 1 billion whose monarchy requested aid against a rising tide of pro-Tau sympathies from its population. The regiment deployed in force and discovered the presence of Necron raiders along with a small Tau army. While results against the Tau forces were often mixed in the open field, the 144th managed with great success to reclaim key areas of the planet's infrastructure, starting with Port Argopolis and culminating in the successful Battle for Saint Ocarian City. It remains unclear what the Necron raiding force sought with the planet. While the planet is still within Imperial care, the Tau threat in the sector is considerable and unlikely to end any time soon.
== Marines Malevolent Interference ==
Starting towards the end of the Namdec III campaign, kill team operations began to encounter hostile Primaris Marines of the Marines Malevolent chapter. Attempts by regimental command to reach out to the astartes chapter have so far only met silence.