I've given it some thought, and have a few more suggestions. I'll divide this post into two sections - the first part will cover general ideas that could cover all spheres and improve the way sphere-related effects are classified, while the second part will cover the spheres themselves.
Part 1 - General Comments
TriggersRather than have magical effects be constant, their intensity/frequency could be strongly influenced by things such as astronomical phenomena, player actions, megabeasts, geological events, seasons, war, death, births, health of the local ecosystem and so on. Triggers could either lead to a gradual waxing/waning cycle (say, a darkness sphere could be tied to the lunar cycle), or a sudden significant one-off event that may coincide with a solar eclipse or some other relatively rare phenomenon. Some things should be very strongly associated with magic and should consistently be a good or bad omen for that sphere. So, if you embarked in a War sphere and your scholar writes a book about a recent supernova you could browse your library (or legends) for the last supernova records to see whether the previous supernova was associated with "War", and if so whether the ultimate consequences were good or bad. This way, once you learn which phenomena are associated with your relevant spheres you know what to monitor. A given phenomenon should only be associated with a single sphere, unless it is an extremely obvious one like day/night or seasons.
A few other examples I have in mind:
- Very predictable cycles such as Day/night, lunar phase, seasons.
- Predictable astronomical events such as eclipses, transits of planets in front of the sun, transit of sun or planet in front of a constellation associated with a sphere.
- Unpredictable astronomical events such as nova, supernova, meteorites.
- Proximity of specific megabeasts to the area.
- Fortress wealth or population.
- Violence.
- Geological events such as volcanic eruptions, earthquakes.
- Number and/or type of trees (or, density rather).
- Presence and number of Legendary skilled dwarves (with specific skills).
- Presence of magic users.
- Location of relevant artefacts.
- Activity of a particular deity (such as descending to earth, returning to heavens, sleeping, shooting lightning at people for personal entertainment, etc. This particular one may be completely invisible to the player).
I'll only list examples of these when discussing a sphere if I think a particular trigger should be strongly associated with that sphere. Otherwise, they should be (semi) randomly assigned at worldgen.
WeatherRelated to environment, but I think this deserves a special mention.
Most spheres may have special types of rain, or rain with particular magical effects. Magical mists may also exist with stronger effects. Water in a particular place may also have magical properties.
CursesSimilar to magical effects, but are dished out by deities or the environment itself rather than other magical users. Curses may be contagious and have multiple different transmission modes, or they may affect only a single individual without transmission. They need not be negative at all - you could get an immortality curse with no ill effects, for instance.
Some thoughts on how curses may be delivered:
- During a time of unusually high magical activity.
- If a deity is angered (sacred tree is cut down, statue toppled, sacred ground desicrated by dwarven feet, hole cut into the face of a sacred mountain, etc). Thes triggers should be consistent.
- Spells backfiring, especially if local magical energy is unusually high.
- Individual does fautsian deal with deity.
- Deity does it for personal amusement.
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And now the spheres.
Metal
Magical effects:
- Transmute metals or other materials.
- Grow metallic plants.
- Transform enemy into inanimate metal object.
- Transform body parts into metal.
- Create "living" metal prosthetic limb.
- Create automatons
Curses:
- Tissues transform into living metal.
- Transform into statue (and die).
- Midas touch, where everything you touch turns to particular metal.
Environment
- Weather
-- (Medium) Metallic hailstones may occasionally fall. These should deal damage as projectiles do.
-- (High) Metallic raindrops. This may be fatal to anyone caught in it, particularly for dense metals.
- Mists
-- (Medium) Transform dwarf into inanimate statue.
-- (Medium) Transmute metal from one type to another.
-- (High) Transform dwarf into collosus of particular metal.
- Other
-- (Low) Unusually high frequency of metal ores, sometimes in rocks they are not normally associated with.
-- (Low) Ores of alloys, such as bronze and steel.
-- (Low to high) Increased performance of smelter.
-- (Medium) Ores change in composition from time to time.
-- (Medium) Ore veins appear where none was before. May also disappear as well.
-- (Medium) Spires of ore protruding from the surface. Large outcrops of ore. Unusually large ore clusters.
-- (High) Magma replaced with particular type of liquid metal.
-- (High) Procedurally generated metals may appear.
-- (High) Underground metal vaults may (rarely) be found, filled with metallic artefacts and guarded by living metal beings.
-- (Extreme) Entire region looks like a large vault with suspended metal walkways and rooms. All surfaces are constucted from metal bars, rather than natural stone.
Trees
- (Low) Foliage takes on colour of metals associated with region, and have a metallic lustre.
- (Medium) Fruit and/or foliage may be made of metal. Cannot be eaten, but can be smelted.
- (High) Entire tree made of metal. Should be consistent within a given species, but not necessarily between species.
Animals
- (Low) Animals with shells may have metal shells.
- (Medium) Animals may have more common metal body parts. For instance, a sheep may have steel wool that can be sheared and melted down. A bird may have aluminium bones.
- (Medium) Non-living automatons guarding things.
- (High) Animals are made entirely of metal. Are not edible but can be smelted.
Artefacts
- Dwarves should always create metalworking artefacts when possessed.
Wealth
Magical effects:
- Transmute base metals into precious metals (not steel).
Curses:
- Midas touch, where everything you touch turns to particular metal.
- Individual becomes obsessed with wealth, and does anything to accumulate it.
- Individual is transformed into a dragon, who then destroys fort and hoards its treasures.
Environment
- Weather
-- (Medium) May occasionally rain coins. (sorry FPS)
- Mists
-- (Medium) Changes personality to increase greed. Increases with each exposure (a less powerful effect could also be a rain effect).
- Other
-- (Low) Unusually high frequency of gold, silver, platinum, aluminium and gemstones.
-- (Medium) Increased frequency of masterwork crafts, increased artefact creation. Particularly strong effect for gemcutters.
-- (High) Smelter mysteriously only produces precious metals, despite other ores being smelted or other objects melted.
-- (High) Enormous multi-tyle gemstones that can be cut into weapons and armour. May require magic to mine.
-- (Extreme) Entire region made of diamond, saphire and other gemstones.
Trees
- (Low) Foliage appears glassy and has an adamantine lustre.
- (Medium) Fruit and/or foliage may be made of gemstones. Cannot be eaten, but can be cut.
- (Medium) Trees may grow coins instead of leaves or fruit.
- (High) Player agriculture leads to growth of inedible gems and precious metals. Players will need alternative food sources, but you'll have plenty of gold to buy it with.
Animals
- (Low) Most animals will attempt to steal high value objects.
- (Medium) Animals may have gemstone eyes, bones or shells.
Other
- Successful forts should be attacked by megabeasts and sieges regularly.
- Dwarves should become insular and distrustful of outsiders over time. A severely afflicted noble may ban all exports and adopt an ultra-mercantillist trade policy (which ultimately leads to fortress starvation if the noble isn't deposed, or requires you to sustain your fort via raids and tribute).
war
Magical effects:
- Increase damage of weapons, effectiveness of armour.
- Fire magical projectiles, summon magical weapons/armour.
- Summon magical soldiers.
Curses:
- Bloodlust, where individual is constantly driven to violence. If noble is affected, they will start wars instead of attacking their own men.
Environment
- Weather
-- (Medium) May occasionally rain blood.
-- (High) May occasionally rain bolts, arrows, daggers, warhammers, and so on.
- Mists
-- (Medium) Changes personality to increase violence. Increases with each exposure (a less powerful effect could also be a rain effect).
-- (High) Coughing blood, inflicting open wounds.
- Other
-- (Low) Iron, copper and tin unusually common.
-- (Medium) If you are not actively participating in a war, procedurally generated goblin-like creatures raid from time to time.
-- (Medium) Warlike civs inhabit the caverns and may invade from underground.
-- (High) Raids turn into sieges. Less frequent if you appease the sphere by actively pursuing other wars.
-- (High) Rain will mysteriously coincide with the arrival of diplomats and caravans.
Trees
- (Low) Foliage appears red, and tree sap has the appearance of blood.
- (Medium) Trees may grow weapons.
- (Medium) Shrubs act as weapon traps, and can be harvested for weapons.
- (High) Trees develop a habit of shooting knives at people. If the war-god is appeased, those people will tend not to be your dwarves.
Animals
- (Low) Pack animals more common, which are unusually aggressive.
- (Medium) Animals have steel claws and teeth, hammers for tails, and other dangerous weapons attached to their bodies.
- (High) Animals are heavily armed and armoured. Projectile shooting animals are not uncommon. Always work in packs, and may siege fort if war-god is not appeased. Will assist player against enemy sieges if appeased.
Artefacts
- Possessed artefacts are always weapons or armour, and are more frequent than usual.