|Ald Redaynia, a ruined Velothi Tower. Note the Giant fungus and standing stones.|
“This tower contains the Bittercup, a unique artifact which is involved in a Thieves Guild quest. The Skeleton War-Wizard here also holds the artifact Vampiric Ring, which casts a very effective Absorb Health and Fatigue spell on touch. Also be sure to check out the flooded lower level which is well hidden as it appears to be blocked off by rubble. There is, however, a path between the rubble and the wall which only becomes visible when you move to the right of the doorway. The key to access the tower's top level awaits those who find this somewhat hidden area, as does a submerged chest full of leveled loot."
This screams adventure locale to me. What isn't there to like? A powerful relic guarded by a high level skeleton WAR wizard, and a flooded lower level? Come on, it's the perfect set up for a one page dungeon, or a one shot, or to just drop on your map somewhere. We can also extract the in-game quests surrounding this locale to provide hooks, and interesting NPCs. The stats I'm using should work with your run-of-the-mill old-school games, some tweaking/addition will be required for other rules (such as 5e).
Let's start with some hooks.
In game, Gentleman Jim Stacey (of the Thieves Guild) asks you to recover the Bittercup from the tower. Currently at war with the Camonna Tong (the local crime syndicate), the guild is looking for allies. A ranking member of the Fighter's Guild, Eydis Fire-Eye, is willing to betray the Camonna Tong in exchange for the relic.
This is a solid start if you have characters with an existing tie to a thieves guild. It's also the most “video gamey" way to introduce the locale - a basic fetch quest.
Let's use some rumors to get the players interested in the locale.
“The dang skeletons are coming out of the groud near Ald Redaynia. They're ruining my day-tour business! Payment offered for removal of said undead."
- Hreirek the Lean, a local guide (and member of the thieves guild)
“Ald Redaynia was once the tower of a powerful grand-wizard. They say his legacy, powerful relics or some such, are locked away inside."
- Tefeb, local drunkard
“We steer clear of Ald Redaynia. They say it's haunted by spirits. Last year a boy drowned near the tower."
- Hagfen, local fishermen
“Ald Redaynia was built by the first Alpi (Elves) who visited this region, back before the founding of the Empire, and long before the tribal dynasties that came before. It's a wonder the tower still stands. Perhaps the secrets to its longevity lie inside?"
- Alded, the local witch
Before we go on here's some info on the relics found within the Tower.
Bittercup: Created by a jovial demon prince who grants power and wishes through ritual invocations and pacts. Drinking from the cup causes your highest stat to increase by 1d6 and your lowest stat to decrease by 1d6. After drinking from the cup, it turns to dust.
Vampiric Ring: This powerful relic, despite its name, was not created by or for vampire followers, but instead by a cult from a bygone age for purposes lost to time. This ring is very powerful, and should attract the attention of cultists wherever it is taken. When used (an action) the ring absorbs the life force (3d6 HP) from the target and restores that much HP to the user. The ring has 2 charges. The charges are restored under every full or blood moon.
War Staff: Functions as a Staff of Power.
The rewards granted for clearing this area are incredibly powerful, thus guarded by incredibly powerful foes. Let's get some stats together for them.
Bonelord: A 4 armed skeleton with some spell casting abilities. Typically found guarding ancient burial sites.
No. Enc: 1d3, Align: Chaotic, Move: 60'(20'), AC: 6, HD: 6
Atks: 4 (Claws) @ 1d6e or Spells. Save: MU4, Morale: 12
Spells: Cause Fear, Magic Missile , Shield, Slow.
Skeleton, Black: Skeletal remains of mighty warriors infused with dark magic to make them stronger than a standard skeleton.
These were published in Barrowmaze, so I can't copy the stats directly. They're basically 6 HD skeletons with Chain and Shields. The can also scream to cause fear (as the spell).
Uldor the Skeleton WAR Wizard: Uldor traded some of his power in life for immortality through undeath.
Align: Chaotic, Move: 60'(20'), AC: 5, HD: 9
Atks: War Staff, Vampiric Ring, or Spells. Save: MU9, Morale: 12
Spells: Shield, Cloudkill, Fireball, Baleful Polymorph
The tower's construction is overall pretty stable, save for the internal collapse on the eastern side of the chamber.
The main entrance leads into the middle level. This chamber is guarded by up to 10 Black Skeletons and a Bonelord.
This floor of the tower is ovular, maybe 60' across, near the center of the far wall is a ramp leading up to the balcony (top level). Combats raging for more than 2 rounds in the middle level will wake Uldor, who casts the shield spell, and moves in to support his guardians.
Characters who spend time checking out the rubble on the eastern wall of this level will find a passage leading down to the lower level. Air flowing up from the lower level is feels damp.
The lower level is flooded (foundation crack near the bank of the river). 4 Black Skeletons guard this area. Moving through the partially collapsed passage could trigger a full collapse, resulting in the utter demise of those caught beneath. 4/6 chance, adjusted by precautions taken by the characters (or use whatever resolution mechanism you're comfortable with).
There's a locked, waterlogged, chest 20' below the water's surface.
Roll a random gem or treasure horde for the contents, or put something else down there.
The top level is a large balcony that overlooks the middle. If the characters take care of the threats on the middle level in less than 2 rounds Uldor will be up here meditating near the Altar. There is also a bonelord and 4 black skeletons. Uldor will attempt to flee with the Bittercup if the fight appears to be tipping in the player's favor.
Along with the Bittercup the altar holds 2 large soulgems (gigantic gemstones) and a huge pile of gold coins.
A more interesting approach would be to grab one of Dyson's Tower maps and adjust this locale to fit. Here are some suitable candidates.