Celestial Cisterns of Forgotten Evil

When the great temples we know now were erected they often built cisterns beneath them. They often used old building materials from other decommissioned buildings and rubble heaps from the old city. Many of these ruins were the ruined temples of the old forbidden gods. You see their decorative columns and great stones used inside the cisterns where people assumed they would seldom be seen. Hundreds of years passed and many cisterns are unused or secret or forgotten. Recently adventurers and nobles who sponsor them have been investigating them. You can spot the style and era of the churches that have these cisterns. They say they feel haunted and weird and haunted.

d12 Current Use of Cistern
1 Used by church for water and rituals of purity for higher ranks
2 Store some old statues, wine, old regalia and documents down there

3 Store for confiscated goods from cults and witches behind a locked iron gate
4 Part of secret escape tunnels for priesthood maybe known only to elites
5 Used for nefarious criminal or heretical purposes in secret with secret passages
6 Tourists are guided by retired murder hobos and you get to see them fight giant rats
7 Fish folk have connected to this by passages and deal with a cult here
8 Cult have a secret passage and worship remains of their old temple
9 Carved text in stone here are fragments of a rare spell and wizards come in secret
10 Monsters have found a way in and live here in darkness, sizable food critters too
11 Treasure was hidden here by old high priest and forgotten but a monster adopted the treasure and uses it as a nest. Perhaps a temple spirit is the guardian
12 Supernatural being laired here d4 1=trapped by binding 2=secret lair 3=has pets and servants and holds court 4=protects a forbidden treasure or inscription or mural not ready for mortals (d4 1=prophecy of next dorm of the evil one 2=scenes from apocalypse that give the location of a hidden weapon artefact 3=location of a titanic Kaiju warns of cult seeks to awaken it 4=reading inscription opens a gate allowing free travel both ways)

d12 Water Quality
1 Quality stored water d100% full currently
2 Reliable quality water from spring, plenty all year round
3 Holy water is harmful to undead but becomes normal if it leaves the chamber
4 Blessed water removes bather's curses but becomes normal if it leaves the chamber
5 Healing water cures a d3 once per day per person but becomes normal if it leaves the chamber
6 Cure diseases of bathers once per person per day but becomes normal if it leaves the chamber
7 Water is stale and carries diarrhoea and vomit-inducing diseases but could be treated or better than nothing
8 Water is tainted and carries parasites causing bloat and gassy flatulence but could be treated or better than nothing
9 Tainted with sewerage and crawling in disgusting life
10 Pool filled with remains of dead and 1in6 times are undead among them
11 Water glows with eerie light and is polluted by some mysterious element
12 Pool is strangely coloured and bubbles with strange fog that can cause mutations. Tainted by d4 1=chaos portal 2=alchemical waste 3=demon idol 4=elemental node

d12 Building Above Cistern
1 Ruined church or monastery, damaged roof, filled with trash where bandits and monsters sometimes camp. Cistern entry may be covered in trash
2 Ruined church outer walls with no ceiling and open stairs to old cistern
3 Collapsed mostly rubble with some walls and a pit into a cistern used as a well
4 Outer walls are intact and the remains of the altar and statue in a middle open area
5 Ancient churches have been converted into apartments and shops or a caravan depot
6 Old worn church still attended by old priests who care for library and relics
7 Monastary or nunnery order above with large grounds of fruit trees, beehives and 
8 scriptorium for where scribes copy holy texts, staffed by priests, nuns or monks
9 Holy library where sacred books are collected, restored and copied
10 Reliquary here an order cares for various remains of saints and artworks
11 Hospital of a healing order where sick were cared for especially pilgrims and crusaders
12 Church specialising in elaborate burials that keep remains of saints and senior church leaders. There are several crypts, stone sarcophagi and ossuaries as well as chambers where bodies are preserved and bones are flensed



d12 Common Forgotten Cistern Encounters (Lv 1-4)
1 Swarm of rats or 1in4 chance of a family of giant rats

2 Swarm of bats 1in6 chance of giant monster bats among them

3 Giant bugs d6 1=centipedes 2=beetles 3=crickets 4=spiders 5=worms 6=slugs or snails

4 Giant marine animals d4 1=crayfish 2=carp 3=salamander 4=toad or frog

5  Some people up to something d4 1=criminals 2=cult 3=church secret business 4=starving cave people sealed here over generations by someone

6 Slime or ooze creature possible in water or drops from above

7 Lesser petty demon protects something here and bullies lower mortal life

8 Undead! 1=skeletons 2=zombies 3=ghouls 4=shadows

9 Fish people possibly 1in4 with human cultists

10 Blind cave goblins hunting fish and lobsters and bugs and rats

11 Blind cave troll washed down here as a severed hand and is scrawny with hunger

12 Humanoid beast folk party d6 1=rat 2=frog 3=lizard 4=lamprey 5=eel 6=beetle

d12 Rare Forgotten Cistern Encounters (Lv 4+)

1 Were rats or 1in4 chance of other lycanthrope d4 1=badger 2=bat 3=frog 4=snake

2 Swarm of stirge live here breeding

3 Cave fisher in vaulted ceiling 

4 Neo-otyg lives in water

5 Cultists with a lesser demon

6 Black pudding

7 Giant cave lizards 

8 Undead! 1=wight 2=wraith 3=mummy 4=vampire

9 Clan of mutants 

10 Clan of trolls

11 Hermit or wizard hidden here for decades wants no human company

12 Supernatural water creature d4 1=water weirds 2= elemental 3=water nymph 4=cave nixies

d10 Quick types of finds
1 Transport
2 Old junk
3 Temple trash
4 Forgotten temples

5 Lost artworks

6 Ecology
7 Old relics
8 Grisly remains
9 Magic Mysteries

10 Elder Evils

d100 Interesting Finds in a Cistern

01 Sunken small boats around former warf

02 Several small boats tied to ramp

03 Small raft with a barrel of wine, box of rations and a bundle of torches

04 Canal boat connects to an underground waterway

05 Collapsed corridor once connected to deep subterranean complex of a former age

06 Tunnel to the sealed tomb complex

07 Crack in bottom connects to an underground river and deep underland lakes

08 Elaborate scaffolding from repairs holding up walls, allows one to reach ceilings and cross waters

09 A flooded staircase goes into a deeper older complex

10 Supernatural ferry tender, silent and skeletal will take you to a faraway subterranean world for a gold coin each
11 Thousands of wine bottles, barrels and amphora

12 Stacks of church records deemed unimportant and in poor condition 

13 Stacks of coffins with poorly preserved dried bodies and stacks of bones and skulls

14 Broken pots, old soiled papers, food scraps and a rat nest 

15 Hundreds of ancient coins in the bottom of water thrown in for luck 

16 Broken old religious statues in piles

17 Broken frightened ancient statues of certification victims

18 Someone has reconstructed carvings, engraved text or murals from old temple bricks revealing some forgotten thoughts of the ancient 

19 Someone has been digging and restoring an idol or shrine of the ancients

20 Clay-sealed vessels containing an older scandalous version of church holy books 

21 Stone serpentine pillar depicting snakes with serpent folk inscriptions of victory over humans

22 Pillar with a bullhead and prayers to old sky god, preying to it will allow air spirit messengers to visit your dreams

23 Stone medusa head blocks used to support several pillars

24 Inscription of ancient foreign wind god but in local art style, symbols and monsters is odd even for the ancients

25 Fish pillar from when the fish folk conquered the surface world for an era, its a giant scaled fish with inscriptions in their forgotten script

26 Ancient headstones worked into walls from graves defiled a thousand years ago

27 Pillar depicting undead including vampires in the underworld, serving of the evil  one in a past ascension 

28 Pillar depicting demons being worshipped by robed cultists

29 Pillar carved with skulls and bones from the age of necromancer kings

30 Great stone monolith once part of a druid stone circle with spiral patterns carved in the surface
31 On the water's edge is a small staircase and an underwater baptism shrine used by the ancient fish cult

32 Shrine with a statue of a horned demon with gem eyes (protected by curses that cause flesh to rot away 10% of HP a day until gems are replaced or the curse removed)

33 Stone crude altar with niches in stone with severed heads in various conditions of decay from missing priests over decades

34 Stone altar with burned skulls and a bronze bloody sickle

35 Stone slabs used as tables with a crude laboratory including a cauldron and magical ingredients with some old formula books 

36 Occult inscriptions from centuries of some cult ritual 

37 Carved block inset in wall of a former cult altar that has still seen some use

38 Cult pilgrims campsite with cooked food and bedrolls and a mix of sleeping and awake cult visitors

39 Crude-damaged statue assembled from others with makeshift altar used by some cult

40 Crude piles of human and animal skulls with candles from some cult ritual

41 Erotic nymph carvings from old temples are considered too racy today

42 Stone block depicting a warrior slaying a dragon

43 Stone blocks showing signs of the ancient version of the zodiac

44 The former front of a temple was worked into wall with mythical creatures and carved writing

45 Relief carving of scenes of holy leader's lives

46 Mural depicting a feast of the gods after the forces of darkness were banished 

47 Glazed tiles on wall section depicting dragons attacking city

48 Gloomy carved scene of all classes before the judge of the dead as equals

49 Statue of a satyr embracing a goat, quite shocking to modern tastes

50 Ceiling has a star map and zodiac signs showing openings in the sky dome to the overworlds
51 Wonderous fungus garden with all kinds of bugs and small creatures, ideal for goblins or pixies to live  

52 Roots have grown through walls and burrowing animals live down here collecting trash and bones

53 Spring grotto here is home to a water nymph and her pets, beautiful calcium formations have made the cistern more like a cave 

54 Bubbling pool of flesh and eyeballs spawns pathetic crawling mutants who fight and eat each other with strange magical machines modern people don't comprehend

55 Pools of slime where oozes and puddings and jelly creatures thrive on strange growth

56 Magical light here allowed trees to grow here and some animals placed here have managed to survive in this menagerie. A shrine to an elder nature deity is here and creatures defend it

57 Colony of kobolds like here feasting on bugs and blind fish. They use tiny boats, scaffolding and walkways to get around which are difficult for human-size foes to use. They have tunnels to sewers where they scrounge for scraps and they breed rats and bugs to eat

58 Sewer urchins live here and have hidden from older gangs and creatures of old city drains. A local spirit aids them and makes enemies forget about the place

59 Water is well stocked with fish and bugs with evidence of tanks for breeding young fish

60 Thousands of frogs live here for the bugs and produce a deafening song if rain comes. Some specimens are gigantic and dangerous
61 Mummified saints with inset gold and jewels, if disturbed will arise

62 Thousands of bones arranged in artistic patterns on walls from former priests

63 Thousands of clay medallions left by pilgrims over centuries and piled up here, some are copper and silver

64 Shrine of a fighting clerical order dedicated to fighting secret cults, an altar and some old records of the forgotten order

65 Piles of weapons and armour of church crusaders hidden here and forgotten during times of trouble 

66 Baptismal font for some secret purification ritual 

67 Court for some ballgame that was a fad once and priests set up in secret and forgot

68 Piles of corroded bronze candelabra, small statues and decorative plates many from long gone religions stored here and forgotten. Some artworks preserve old church history 

69 Statues taken from enemy religions and stored here, some have offerings left for them

70 Gibbets with remains of cultists who suffered in these cages for many years before being allowed to die. Possibly unhappy spirits remain
71 Collection of sealed bottles with ancient writing on them, many hold spirits of slain enemies of spirits captured during excorcisms

72 Moulted shells of giant insects in piles possibly a colony nearby

73 Cobwebs everywhere and mummified cobwebbed corpses suspended. Giant evil spiders lived here once and still might

74 Hundreds of headless skeletons of executed heretics in chains 

75 Remains of huddled priests who hid here once and starved possibly haunted

76 Bodies of plague victims stacked here for disposal and forgotten long ago

77 Serial killer has been operating a homemade torture dungeon and even has chained victims and a strange idol and altar erected

78 Shelves with jars of freak pickled creatures and dried exotic creature corpses and remains of some kind of lab 

79 Stone coffins with unknown species corpses and chests with some strange relics

80 Fleshy sacks suspended from the ceiling are hibernating catfish folk wizards awaiting the right time to conquer a new civilisation. Other fish cults protect them as chosen ones of the fish gods
81 Broken portal once used to travel between temples but ruined to avoid some enemy plot

82 Holy weapon of legend sealed in a force wall 

83 Holy book protected by golems from thieves unless a worthy priest comes to claim them

84 A pit with a bound lesser god trapped by holy magic long ago. The god is hungry and some cult have been trying to help the god with food and trying to damage sacred sigils

85 Statue of deities servitor than can with a sacrifice be used to contact this holy spirit for knowledge but only one per person ever

86 Painting of scene of ancients that was locked away for its magic properties. A small world inside has many imprisoned persons who failed the gods but perhaps it is time to free them

87 Waters contain spirits of past priests who can be consulted if brought wine or blood

88 Chained sphynx here is obligated to answer one question while imprisoned, it promises to answer more if freed but it lies

89 Statue of shedu protects cistern from evil and spirit can animate stone as a body to act. It may aid good adventurers 

90 Magical holy shield is held behind a barrier of holy fire. A worthy wielder must petition an angel who decides who is worthy and has a statue here
91 Statues of frightened explorers and priests here due to the lair of a monster with petrification powers

92 Demon lives here acting as a priest of a demon cult with a statue of its lord and a bloody altar scattered with bones and dried blood

93 Cult dwell here in robes with masks and are imbued with sorcerous powers in return for their souls. The entity they worship may manifest if enough people die in here at once

94 Demon cult pillar, if you sleep here you have visions of ancient rites that if mimicked help the evil demon return to existence again and even visit the mortal world

95 Mutagenic mist here has changed life into strange cave mutants better suited to life in darkness. Creatures here are very odd and primitive and some dangerous. Strange inhuman broken statues and urns are found broken in the black mud and slime

96 The cistern is partially in the land of dreams and darkness. Shadows may enter the world here and sometimes beings from dreams or nightmares appear here to try and anchor the dreamlands to the waking world. Some dreamers come here to sleep in hopes of making dreams come true (which is often bad). Perhaps various relics here could shift the world warp here to less horrible or destroy it

97 Portal to elemental plane in a slab of stone but requires user to read the prayer to activate the gate for a period of time

98 Portal to hell or a demon plane guarded by an angel

99 A sleeping titan or monster is chained here awaiting some certain time like the apocalypse. Was imprisoned by the gods

100 A gilded cage with an immortal saint imprisoned here so he cannot run away to some other temple or go on a final quest to the celestial court. Will answer questions but guarded by golems