I ran Night Below back in the late 90s.
Nico - male wood elf ranger (half-drow, no special powers... long story)
Allanon - male human priest of Mystra
Mistry - male human mage
Lothar - male human paladin
Rufus - male halfling fighter/thief
Drugar - male dwarf fighter
We made it to the Underdark lake where the aboleth dwell, even adventuring with none other than Dove Falconhand for a time. In their explorations of the surrounding caverns, they stumbled upon an ancient dwarven tomb. Their greed led them to deeper excavations (despite the protests of the dwarf...). Even when they came to the vault with "Great Foe" inscribed upon the adjacent wall, the wizard shattered the old wards locking the vault, and a drow lich was awakened. Long story short: TPK. :\ The party priest (Allanon) had to leave early (some clerical teleport/dimension door-type spell), before the poo hit the fan, so his PC was the only one left.
I read about the "Great Foe" angle in one of the FR sourcebooks. I forget which one, but it stated that some dwarven cultures are known to entomb their greatest foe along with the honored dead, so I used that in the game.
At the next game, Allanon scried the party, learned of their fate, buffed, and opened a doorway to the lich's tomb (as the lich couldn't leave due to other intact wards). With half his spells and no spellbook, the lich was unable to study, and only had what few spells left since the destruction of the tomb robbers. With the translocational portal open, Allanon dumped four fireballs into the tomb, crisping the lich but not destroying him. The priest stepped through the portal and into the tomb, and a brief spell exchange led to a grisly melee. Allanon prevailed ultimately, and didn't spend time searching for his phylactery (which could be anywhere on or under Faerun). He then healed himself and searched for the party bodies. They were gone, spirited away by a demon summoned by the lich to an unknown location for some unknown reason.
Allanon decided to hire a new party to join him in finding and rescuing the bodies (and magical items) of his slain companions. The new party consisted of the following:
Allanon - male priest of Mystra
Evisceral - male half-elf rogue/mage
Coldar - male deep gnome cleric of Flandal Steelskin
Magnus - male human diviner
Lariolas - male elf fighter (archer kit)
Theroden - male half-elf mage/cleric of Azuth
After scying revealed the location of the bodies, the PCs plunged into the Underdark, trekking down several miles to a huge drow stronghold. They fought through scores upon scores of drow, derro, bugbears, and orcs, making their way to Allanon's beloved companions. Ultimately they stumbled into a central chamber containing a glabrezu demon, an ultra-illithid (or ulitharid, or something similar), a drow priestess of Lolth, and the drow lich in another withered corpse. The glabrezu stunned the entire party with one 2E power word stun (devastating), and the campaign ended there, with the ultraillithid eating out the brains of everyone but Allanon, who's mind was reamed for the secrets of the silver fire he carried within him (long story).
We started with 3E roughly two months later. During one 3E game session, I brought back Nico and his half-brother Zinzer as Zin-carla assassins who tried to kill Lord Mourngrym during a large-scale drow/orc attack on the Twisted Tower (long story). Dove wept over his butchered corpse.
