The Forsaken

Summary

"It's time, are you ready?"
He wasn't sure if he'd ever be, but he nodded all the same. The priestess stared at him, the moonless night leaving her armored visor dark and foreboding. Wordlessly handing him the banner's staff, she turned and led the way forward. He followed after, hefting the temple banner high up. The road ahead of them both stretched on, weaving through the broken remains of the village.
From the priestess' one hand hung a censer, an iron chain connecting it to the flail head hanging off her other hand. She swung them back and forth in a slow, ritual motion that supposedly helped calm the dead. A clinkling of chains sounded with every heavy, thudding boot step.
"Can–can I ask something?" he ventured hesitantly.
"Mm. You're a new acolyte, yes?"
"I am, madam superior."
"Very well, what is it?"
"The books, erm, talked a lot about what to do with the undead. There wasn't much about why they happen. In the first place, that is. Or why they're called 'forsaken'," he said in a rush, tingly and nervous of embarrassing himself. The need to know, however, proved stronger.
"The 'why' is it ... Hm. Imagine our world–your family, friends, city, everything you know–as a house. We all share in it, until there are those who are thrown out. Or, they leave, and never return. These wretched souls, whether living or dead, are called 'the forsaken'. For we, who live in that house, have forsaked them."
"R-really?" he couldn't help asking dubiously. "But, there's always somewhere that'd take them in, right? Or help them?"
"Those in pursuit of evil are like a rot, spreading to everything they can consume. Those left to die, unloved and unburied, burn with a fiery hatred. Perhaps it is they who forsake not only who they were, but the person they could've been, to become something far worse."
He wasn't sure if she was simply thinking aloud or talking to him. It seemed a difficult thought to follow, but the sound of wood snapping caught his ear. The two of them looked over to the collapse arch of a house's entrance. A figure, illuminated by the priestess' burning censer, shambled toward them. Cold fear seized him utterly for a brief moment, but the priestess struck first, hurtling her flail toward the undead's head. A meaty, bony crunch followed, and it collapsed to the ground. Blood dripped from the iron as she reigned it back in, then resumed walking forward.
Staring at the downed figure for a moment, he hurried after her again.
"All the same," she said solemnly, "no matter the why, it falls to us to rectify the wrongs. Peace for the dead, and justice to the crimes that were wrought. And, like any person, sometimes they won't listen without a little force."

Upon Veltrona, the Forsaken encompass evil in its most destructive forms. For many cultures, this is usually the returned undead: vengeful souls who, having died horribly, dishonorably, or worse, come back. However, it also includes the living Forsaken, people that have committed the foulest and most unforgivable acts for personal gain. It is not simply a way of naming them, for becoming a Forsaken is a visceral matter that affects both body and soul.
In some respects, it is a transformative process holistically compared to the Relentless and their abominable mutations. However, mindlessness is an uncommon thing; the Forsaken are people, for however distorted, changed, and ugly they've become. By the nature of their existence, they're in a downward spiral, seeking to drag others under. There is no future, nor hope, for them, and so they do not care about the consequences of their actions.
Among the living Forsaken, it is no mere accident that they transform into wretched, heinous creatures. Some, caring of their 'looks', maintain a facsimile of what they used to be. Vampires are one clear example of this, incarnations of greed and lust for power, beauty, and prestige. Others turn into something ever more different, perverse, and wrong, yet somehow alive. Their pursuits often become obsessive madness, their grasp on reality slipping as they feed their hunger more and more.
Those who can resist or overcome their mind collapsing as they pursue evil are truly rare and extraordinary. They're also among the most dangerous of all Forsaken, living or dead, and some of the greatest foes that Veltrona has ever seen.
In contrast, the Forsaken undead are far more varied and different in their motives. The vast majority are often simple people who, dealt a cruel hand, bear terrible grudges and resentment. How a person exactly returns as an undead is not understood, and appears to happen quite randomly. Those who've died horribly, or been mistreated after dying, are simply far more likely than any other to return. Hence, many cultures consider proper funerary practices and respect to the dead as vitally important.
It also means the good treatment of people, as a whole, becomes much more important. The poor and impoverished dying en-masse can result in a lot of undead emerging from out of nowhere. Bereaved and wronged, they lash back at family, friends, and people they once loved in blinding hatred. If not quickly contained, this feeds into more violent and wronged deaths, creating more undead. This simple fact belies how horrifyingly effective it is, creating an exponential calamity that has destroyed countless cities. It's something that has even been weaponized deliberately by people, for how horrible such a thing is.
Natural disasters, famines, Relentless assaults, and other massive events are even more troubling for these same reasons. Sudden, painful and violent deaths can turn even well-mannered and treated populations into raving, vengeful undead. Thankfully, it is not usually an immediate problem compared to other situations. Disoriented, lost, and confused, the freshly returned undead struggle to accept their own deaths. Priestesses, shamans, and others can much more easily guide them to a gentle rest.
The problem is, being undead entails losing one's past self, no matter how much they resist. Eventually even these 'peaceful' undead will deteriorate into violent, life-hating beings who earnestly believed were wronged. It's a race against time to see them laid to rest before they fully lose themselves. Hatred begets more hatred, and even a few malevolent actors can trigger a devastating cascade.
The worst follows for those who somehow 'survive' as an undead. Driven by their unyielding malevolence, they claw their way to profane power. It is from these vile ranks that more powerful undead emerge, the likes of nekrokin and Grave Queens. Unburdened by morality or ethics, they wage terrible wars to slaughter all they can. In the end, they will either win, or die trying, and there can never be peace if they are around.
For a more detailed breakdown of the undead and their manifestations, please refer to the specific entries in the Forsaken category.

The Forsaken Undead

Zahmtorla Codex

Created during the age of the Imperium, the Zahmtorla Codex was fashioned by wokma scholars studying the Forsaken Undead. It's a rare example of something universally praised from the Imperium, as the Zahmtorla became a significant tool against the undead. The wokma created observable hierarchies, patterns of behavior, methods of containment, and various means of quelling the returned undead. Most of these favored martial ways in doing so, as proactively destroying the undead can resolve them the 'quickest'. Not all undead can be stopped, or at least easily, through pure violence.
Thusly, while many cultures would ultimately use their preferred methods, the Zahmtorla's vast details helped refine them. It also opened the way for common exchange between disparate cultures, who struggled with more exotic or unusual forms of undead. Since the Zahmtorla was spread across the Imperium's territories, it was also translated into a huge amount of languages. Ironically, its second greatest use became a translator's point of reference. While lingual drift is always a problem, the Zahmtorla provides a strong record that's been referenced countless times.
With regard to the undead, the Zahmtorla Codex helps to broadly establish their two main 'families', and then their many variants.

Surnki and Zahmka

Surnki are instinct-driven, singular purpose, or otherwise near-animal like undead. Although they may resemble people by far and large, much of what makes a person is missing or distorted. The dismissiveness of dragonkind considers them quite lowly (hence the name), but it is not wholly accurate. Parts of who they were still remain, for however distorted they have become, and for how hopeless some find it is reaching out to them. All returned and skeletons would fall under this classification, for example.
Zahmka are people-like, thought-capable undead that are arguably sapient. They're often the most dangerous as a result, being able to strategize, use magic, attract and control surnki-type undead, and be driven by more than instinctual goals. Grave Queens, liches, and similar undead all fall under this category. Most zahmka undead exhibit entirely new personalities, having either no origin in who they used to be, or amalgamations into something different. It is often seen as a mockery of life how they act and behave.

Types

Undead can come in all sorts of varieties, changed by circumstance or deliberate design. Normally, the manner of their death and subsequent reanimation is what affects them the most. Broadly speaking, common themes start to emerge, as people who die horribly in similar ways produce similar undead.

Ravenous

Those who've died of starvation and over consumption, the ravenous are solely focused on devouring anything edible they find. Of all the different undead types, theirs is among the most destructive to life. People, animals, and anything they knew to be worth eating are their sole focus. Spurred on by their hunger, they're also the most physically active and capable of the undead.
They're also unfortunately one of the most common types people encounter. When famine and/or starvation strikes, the ravenous dead will emerge almost everywhere. Spreading like wildfire, those they consume in turn usually become more ravenous. If not snuffed out quickly, entire cities can be devoured from the inside out in a matter of days. Thankfully, their unsubtle nature makes finding and eradicating them much easier to do.
Ravenous also have little concept of allegiance, and exhibit a lot of animal-like behavior. Infighting is common; they'll turn upon their fellows if nothing else is available. They'll also branch out and roam, actively hunting for prey. Without the presence of higher functioning undead to command them, they're loose cannons, and can often wipe themselves out easily enough.