Ammahud Shelomoth

A necromancer surpassed in the annals of history only by Naraoch and certain Pontifices of the Grand Mausoleum, Shelomoth was an Archon of Anthur-Ro and key contributor to the success of The Trilune Fellowship.
Fostered at Anthur-Ro at the request of the warlike tribe of nomads into which he was born, Shelomoth hailed from the tundra of the region now known as Aildean. His aptitude for necromancy and his command of the Weave lighting the boundaries between life and death marked him from the start. Though his people embraced him, their fear of the dark energies that seemed to surround him prompted them to undertake a great expedition to bring him to the mages of the Council for his own safety and that of the tribe.
Shelomoth rose quickly through the ranks among the mages. His dry wit and dark sense of humour endeared him to his fellows, and his raw power and capacity for singleminded focus resulting in his professors being incapable of finding adequate challenges to temper his ambition. In his fourteenth year at the tower, that gap was filled by the Omnicide.
Shelomoth's ingenuity and valour in both conceiving and bringing about the binding of the Lich Queen left him among the most trusted allies of the Trilune Fellowship, and his Archmage, Bo Blackchin, in particular.
When Eldath took upon herself the grave duty of soliciting the Fellowship's allies for eternal service, Shelomoth was an obvious early choice. He was a necromancer of unmatched skill and a close friend and ally. There is some uniformity among chronicles in noting that he was the only sentry that joked upon accepting that duty, asking her if that indefinite isolation would not drive the rest of the world mad.
Shelomoth's warrior kin, highly distinguished in combat against Naraoch's forces, volunteered to rejoin him behind the seal. The reunion was said to have been an emotional one, and together with their favourite son, the tribe consigned itself to the deep and the defence of the realm.

Encounter with the Ladies' Hiking Club

Twisted from long years of living below the surface and endless experiments in the preservation of immortality, Shelomoth encountered The Ladies' Hiking Club under the not-entirely-incorrect impression that they were more invaders along the lines of the Corrans that had methodically slaughtered their way through the Lighthouse just two days prior.
After a brief but torrential combat, Shelomoth fell at last. He seemed for a moment to come back to himself in unspoken communion with Beulah Garland, and offered a gesture towards the hidden panel at the rear of his chapel's altar. Behind that panel, the Hiking Club came upon an orrery that, properly decoded, revealed the location of all lighthouses across the world: a list that Decima Overmere yet covets.

Logbook and Eagle Orb

Upon his final death, Ammahud Shelomoth dropped two artifacts: his logbook (exclusive of certain pages that had been stored in the vicinity of the Mirror of the Darling Never, which, taken together, complete the tome) and a glowing Eagle Orb.
Tome of Ammahud Shelomoth

The tome he carries is four inches thick, dense and handwritten in a sharp and rudimentary early Yishanim script. Its pages are holding together commendably well given the amount of use it has seen. Only Vega can make this out at all, and even then haltingly. But Beulah and Torwall can help translate some of the more obscure terms and identify patterns that engage the Weave and separate experimental or observational text from spell script. Getting through all of this is going to be a large group project, but for now let’s just see if we can get the gist of it...
With those two helping to interpret the words you sound out, you can have advantage on an Arcana check.
{ARCANA DC 10 - pass} It’s necromancy, obviously. Lots of stuff about bodies, bones, spirits and essences. It’s not just his handbook for raising skeletons, this is almost like he was trying to write the textbook from 101 to grad studies. Also, even though it’s all in his hand, he digresses into other languages here: Elven, Sylvan, Abyssal, a few others you don’t even recognize.
{RELIGION DC 14 - pass} It’s not just his own writing, these are excerpts from other works. He’s quoted several other texts and even scrolls and picked them apart. With a little bit of effort - actually a lot of effort - you should be able to make some necromancy spell scrolls out of what you find in here. You find some references in here to the afterlife, as well, and illustrations vaguely resembling some of the structures you’ve seen in your missions to Hell. Typical necromancer, dealing with everything from poisons to immortal souls.
{ARCANA DC 18 - pass} Whoa, this gets into a lot of dense detail. It’s so dry that your eyes almost skip past it in search of easier and more exciting words, but there are detailed incantations here attempting to come up with something almost like the genetic code of a soul. That’s an interesting idea, trying to figure out exactly what a soul is made of.
{RELIGION DC 22 - pass} Your eyes are just about to leave that page when they flit back. Something trips your peripheral vision and you land on a sentence you just read a moment ago. It had said, in the Old Tongue, “L’hiratot lekha oleh sherut melon”, but now it reads “L’hiratot lekha oleh olabut melon”. Instead of saying “the measurement will dictate the consistency of the animate matter raised”, it says “the measurement will dictate the consistency of the undead matter raised”. Something changed that word, but not its meaning, and caught your eye.
It wanted to catch your eye.

After a challenging attunement, requiring arcane and divine knowledge in addition to a working knowledge of handwritten Yishanim language, the student of this tome may be inspired by it and may gain new spells from the Necromancy school.  In the event of an exceptional success, however (three straight successes with greater than 5 clearance over the required DC) may be possessed by something within it.  The spirit within seeks domination over its newfound home in the reader's mind, but can itself be dominated through sufficient force of will.  If it is brought sufficiently to heel, its master will have dominion over the spirit's facility with extraplanar force projection specifically into the halls of the dead, in addition to its fluency with necromancy in general.
Orb of Shelomoth
The Orb seems to attract the Green Dream.  The aurora that emerges from cracks in creation seems to be drawn into it through some unknowable force.  When it is 'charged' with this essence, the Orb grants its owner the ability to cast three charges of Conjure Minor Elementals, Conjure Woodland Beings or Dimension Door before needing to be recharged.  The real-world effect of sucking Aurora out of the world is still unknown, but it does not appear to have any damaging or harmful effects.