Good rule of thumb for contributors: if you can't associate your contribution to the setting with some sort of power black metal song, it may not be a good fit for the setting.
Forschungsgemeinschaft Ahnenerbe ...and the Earth will tremble again.
Introduction
None in the American continents remembers the times of the Sixth World War, long before the End. During the second and third centuries of the fourth millennium, the swastika flags flew over New York and Washington, two of the many cities of the east coast reduced to ruins by the onslaught of the war. The soldiers of the Fourth Reich marched onwards, and it took many decades of war to halt their advance, and force them to retreat to the ocean's shore, bunkering down around the captured White House and Manhattan. From around this time, the records of the Old World end, as the End began. Yet, in the midst of the raging chaos, a single signal was sent to Berlin, to be picked up a long, long time later.
A distress call.
In the murky skies of New England and the Mid-Atlantic, the looming, immense figures of the zeppelins appeared out of the clouds, as monoliths towering in the skies. The infantry battalions soon followed, making landfall in swarms and setting up a network of outposts in the region. From here, the heavy tracks of the Panzer Divisions soon began to advance westwards, and the black banners of the Fifth Reich were raised for the first time in Amerika. The flood comes.
Military Forces of the Fifth Reich
Infantry Divisions
Meine Ehre heißt Treue!
Waffen-SS: the main bulk of the Ahnenerbe's infantry forces, these soldiers are harshly trained in order to achieve high standards of discipline and courage. Little armored and equipped with a varied arsenal of weapons (including all kinds of small arms, anti-tank weapons, and grenades), they rarely attack on their own, but rather support the armored divisions in their attack, operating in small squads each led by a Scharführer. Some divisions of the Waffen-SS include the Totenkopfverbande (specialized in guerrilla urban warfare and equipped with heavy flamethrowers), the Karstjäger (a scout division mostly composed of snipers and infiltrators), and the Nibelungen (an assault corp equipped with heavy machineguns and anti-infantry weapons).
Panzersoldaten: as they are initiated into the mysteries of the Ahnenerbe, veterans of the Waffen-SS are welcomed to join the ranks of the Panzersoldaten-Division. Clad in heavy power armor, allowing them to operated even in fully contaminated or irradiated areas, the Panzersoldaten are the special infantry forces of the Fifth Reich, equipped with heavy weaponry and sent to lead the charge or hold the line in the most heated areas of the battlefield, sometimes advancing deep behind enemy lines or resisting even when surrounded by foes on all sides; they still retain the organization scheme of the Waffen-SS, and operate in squads led by a Sturmführer.
Sturmtruppen: becoming one of the Stormtroopers of the Ahnenerbe is among the highest honors an SS soldier could strive towards. Numbering only a few dozens, the Sturmtrupper are equipped with a state-of-the-art suit of heavy armor, including a set of powerful reactors and wings, allowing them to fly for short distances on the battlefield, landing on the enemy like a furious fist. Armed with the heaviest weapons their armor can carry, such as rocket launchers, chainswords, and gatling guns, the Sturtruppen tend to attack the enemy from a close distance, often engaging in brutal melee. The Sturmtruppen's assault is led by a fearless Sturmbannfuhrer, and all of the members of the divisions are intiated members of the esoteric cults of the Ahnenerbe.
Panzer Units
Es braust unser Panzer im Sturmwind dahin!
Schwerer Panzerspähwagen Sd. Kfz. 622: lightly armored and relatively fast, this vehicle is used by the Ahnenerbe to quickly bring infantry troops to the frontline; it can be equipped with an anti-infantry machinegun or an anti-aircraft gun. Highly versatile, it can climb almost every kind of terrain, but its light armoring makes it a target for heavier weapons.
Panzerkampfwagen IX Tiger: the most iconic tank of the Ahnenerbe Panzerdivisions, the Tiger, an evolution of the omonimous WWII-era vehicle, is characterized by its flat, cylindric turrent and its twin cannons. Offering a good compromise between heavy armor, movement speed and mighty firepower, it is often considered the masterpiece of the Fifth Reich's engineering, and can be seen on most battlefields where the SS are engaged, with Tiger divisions often being at the forefront, leading the attack. Despite this, like other heavy tanks, it is vulnerable to mines and anti-panzer infantry.
Panzerkampfwagen E-700 Löwe: the Tiger's companion and heavier counterpart, the Löwe, created from the merging of late WWII-era superheavy tank prototypes, is a slow-moving, heavily armored tank, armed with a long-range cannon, giving the panzer an excellent firepower. The Löwe is not unlike a small moving fortress, and is used to obliterate fortified positions or other tanks, or to defend strategic locations. However, its great weight does not allow the Löwe to tread too rough or swampy territory, and its slowness makes it an easy prey for anti-tank infantry and faster vehicles capable of destroying its armor.
Air Forces
Wir sehen uns in Walhalla!
Messerschmitt Me 266 Komet: originating from a WWII-era design, the Komet has become the most prominent fighter and interceptor of the Luftwaffe. Lightweight and fast, propelled by an advanced rocket engine, the Komet is armed to face other fighters and bombers alike, and can use its great speed to avoid anti-aircraft: however, it is unfit to attack armored targets, so it is often sent to escort bombers during their missions. Its small weight and size allows it to be easily transported in great numbers in the hangars of the zeppelins.
As I said, I was thinking about considering the skeletons as a race, with a model of society and culture distinct from that of humans. I might also add one or two "minor" races, but I'm not sure about that.