The lich is a form of sentient undead who cannot be killed until the object containing their soul is destroyed. The Electric Lich borrows the concept and moves it into the CE

Archbishop Midas of the Jovian Temple was a scourge to necromancers of all kinds, from the genuinely malicious to those who were merely talking to the dead with the consent of the families, sending many to burn at the stake, so after his death they took their revenge...and created the Bone Idol.

An ashen grey willow with pale leaved tendils obscuring it's gnarled trunk. Sitting in the mire of great swamps, rare even in it's natural environment. The Banshee Willow's bark is known to have magical properties. Travelers beware, these trees seem to attract ghosts and other unsavory undead.

A shuddering heap of corpses and rotting soil, Logeko the Vile is a demon of of death and decomposition

An explosion rocked the city walls as if a hundred mages unleashed their fury upon the peaceful people of Souls'e Province. An instant silence in the wake of the blast was nearly as loud as the noise that erupted right after as another series of explosions followed the first. Then the screaming began. Low at first, then became physical as if a wave of noise punched us all in the gut and sent us to our knees. Even the guards began running, screaming. 'The people, they... they are murdering everyone. The city has gone mad. RUN!!!'

PCs one way or another often end up disturbing tombs and barrows and robbing graves. So what might they find there?

The Regal Tombs of Orbis were the place where the richest of the rich were buried, and Bert was sure that if he could break in to a recent two-month old burial he would be wealthy for at least the rest of the year. Since tomb-robbing could get somebody the gibbet, he had gone alone, and now he cursed as he fought hand to hand with the bulbous, distended, decomposing corpse that had leapt up when he tried to steal the grave goods and now beat and clawed at him and swiped at him with a rapier. Every wound it inflicted on his body, he got a little weaker and to his horror, it grew a little stronger and a little less rotten. Not long afterwards, a seemingly living man left the tomb, leaving the body of a grave robber behind. A body that would soon rise...and walk...

The spell Animate Dead has existed for a very long time, with many variations. The spell Cadaverous Companion is another such variation, but it is tailored to the animation of companion animals, rather than human corpses

You can't miss it, it's eight feet tall, glows in the dark and breathes ghost flames. Even if you're blind it utters blasphemies and damnations, a black poetry of the underworld. If you're deaf and blind you can feel the cold in the air when they turn up.

Stronghold made for the liche Haukagaron. He was betrayed at the last and Castle Kaukenn was pulled into the Abyssal realms.

Known fully as 'Nind Vel'uss Tahcaluss whol nind ehmtu siltrin' or 'They Who Hunger for Their Own Flesh'

The Odaneimo Mountains aren't exactly the sort the bards talk about, they dont tear at the sky or trip the gods. They are still tall enough that you just can't go hiking over them. There are just two passes through them, Oshen Pass down in the south, and Zoran pass, in the north. It would be worth a pretty penny if someone could find a middle pass through.

Diad, Teamsters Guild-boss

'I knew Lwausf would be angry when we banished him, but I didn't see the whole undead-bearman-projectile thing coming. Looking back it was kind of inevitable. '

Prince Gorim, Lord of the Mounatian Hall at Silverspike

The unnatural offspring of a zombie father and a human mother.

All Maire wanted was to give her husband a child. She wasn't about to let death stand in the way.

Once upon a time this sword may have been a sight to behold, but no more. Rust and decay now tarnish the metal of this forgotten relic, and those who stumble upon it are more likely to toss it than use it.

'I take it ye've ne'er fought a Semblance. Nasty undead fiends they be. 'course, they don't look undead. They don't have gleamin' bones, or rottin' flesh. No, sir! The Semblance looks just like you or me. Except for when its tryin' ta get you. I take it ye've ne'er fought a Semblance. If you had, you'd be dead.'

-Old Gerald, man in the pub

Ah, you are awake now I see. Wondrous news. I realized that you have no idea what is transpiring so I will be blunt so you may understand it. It is rumored that you are one of the best jewelers and metalsmiths in the region and for that you are lucky enough to have been chosen to create an item that will change the world. And afterwards, you shall be set free. My word on it.

Decanus Kormak

I watched in horror as the final pieces were infused together with dark magics granted to the mighty Kormak by Shivenhusk Himself. The head from Lord King Vyrkril was placed on a base of blacked bone and thrust into the cold burning fire. I swear I hear it scream in agony. Decnus Kormak smiled at his late king and when he pulled the chalice from the blue flame bare handed, he clutched it covetously. That alone made me afraid.