@IEB: I got age of emptiness from a world where no land creatures could spawn, leaving FBs as the "only things alive" in Legends. Emptiness is also what was received from the ‼Science‼ of Datan Worlddoom killing every living thing in Adventurer -- but the Civs were not flagged as dead, so migrants and traders still came in Fortress mode.
Test 1
From basic pocket Island: 1 civ, no (semi)megabeast caves, no titans, 3 clown types, 13 night creature types, ignore beasts dead for stoppage.
Result: Age of the Dwarf -- it seems Night Creatuees do not matter for age. They will be left on (and clowns restored to 13) for the Final generation, after Age of Death is achieved without them slowing worldgen.
Test 2
As above, but 1 titan with no attack requirements.
Result: The Hill Titan Age -- blighter didn't die. 49 living historical figure means the dwarves were stomped.
Test 3
As above, but 13 titans -- I'd had some luck with this number before, and a singular attack requirement of 20 pop.
Result: Age of Myth. The dwarves don't seem to be killing titans very well. (or possibly they never drew its attention: see below)
Test 4
Titans turned off, but semimegabeasts back on. Hopefully, giants and minotaurs will be easier prey. Semimegabeast caves: 7. I've also turned night creatures and clowns off to speed up worldgen a little. if I get the age of death, I can turn them back on and gen again to get a world with more ‼Fun‼
Result: Age of the Dwarf, with 35 living figures, 830 total. Since only about a dozen could be FBs, this suggests that the dwarves have a stable population of between 10 and 20.
Test 5: as above, but lowered attack requirement to 10 population and increased semimegabeast caves to 13.
Result: Age of Dwarves, 4422 total historical figures generated with 4383 dead.
Test 6: As above, but replaced the semimegas with titans now that I know the stable pop.
Result: Age of Myth. 6793 total historical figures; 6747 dead. Of the remaining 45 figures, if we assume 13 titans and 12 FBs, we get 20 living dwarves.
Test 7: Capped titans (1000) with completely unreasonable aggression (attack population of 1)
Result: Age of Myth: The dwarves survived and thrived on this. However, as the world started with under 1000 historical figures, we can assume
Test 8: No attack requirements, 1 civ, pop cap after civ creation of 0, 1000 titans, megabeast, semimegas: no non-mountain caves and enough mountain caves for all megas and semimegas.
Result: Age of Myth; 480 Historical Figures with 414 dead: the remaining 66? with such low numbers over 10,000 years they cannot possibly be dwarves! Checking legends (world can be played in any game mode)... The last dwarf died in 17. The legends list is populated from then on by the births and deaths of named cougars, bears, wolves, trolls, giant bats, troglodytes, cougars, and jaguars who did nothing but wander and die of old age, plus the occasional cave dragon still alive. there were far FAR from 1000 titans
Amusing fact: the dwarves are listed with "He/she was one of the only ones of his/her kind" rather than "first". They all appear to have been killed by the beasts.
Test 9: pop cap of 0, one civ, no beasts of any kind
Result: the Age of the Dwarf, 688/712 figures dead
Test 10: as above, but 5 civs.
Result: Age of the Elf
Test 11: As above, but dried out so elves can't spawn.
Result: the Golden Age. The last dwarves died in 141, but at least one was born. Goblins continued to be born and die throughout all 10000 years of history.
Result 2: This test was accidentally repeated. The world ended in the Fourth Age of Fairy Tales, with humans as well as goblins surviving
Test 12: As above, but civs 2 and hope for humans (this experiment will be repeared 10 times, or until Age of Death)
Result 1: The Dwarven Age
Result 2: The Age of the Dwarf
Result 3: The Age of Dwarves
Result 4: The Golden Age
Result 5: The Age of the Dwarf
Result 6: The Age of Dwarves
Result 7: The Age of Fairy Tales (21 living units, thousands dead). Playable in any game mode. Legends check says the world started in the Twilight Age, and progressed to Fair Tales quickly. Humans only survived -- why is it not the Age of Humans? Region Folder saved for ‼Science‼
Result 8: The Age of Fairy Tales... looks to be those darn humans again.
Result 9: The Age of Fairy Tales
Result 10:The Age of Fairy Tales
Test 13: 1 civ, playable not required, dry world, hope for kobolds(?); Repeated 10 times.
Result 1: The Kobold Age, 19 living units, adventurer or legends (no fortress mode). 12 FBs, a Harpy, a Cave dragon, 4 Trolls, and a Troglodyte populate legends as the survivors. the kobolds all starved in 4, as expected.
Result 2: Age of the Kobold
Result 3: The Age of Civilization: Humans spawned, playable in adventurer or legends. Legends says humans are still alive.
Result 4: Age of the Kobold. I swear the game is mocking me
Result 5: Age of Civilization. Numbers suggest the humans made it (unlike the kobolds)
Result 6: Age of the Kobold
Result 7: The Age of Dwarves (By the numbers, they did not make it)
Result 8: The Age of Goblins (Alive or dead? I can't tell)
Result 9: The Age of Dwarves (dead)
Result 10: The Age of the Goblin (Extinction unverified)
Takeaway: It seems humans are unique: they to not get their own "age of x" but rather usher in Twilight/Fairy Tales/Civilization. I might need to have humans and dwarves to get a playable Age of Death...
Test 14: Clean start: beasts/NCs/Titans/Clowns removed, no beasts dead for stoppage, 10k year history, 0 civs, require playable
Result: World generator unable to place controllable civ. Allowing this rejection type. Final Result: The Age of Emptiness. Unlike the Waterworld Age of Emptiness, this is playable in Adventurer, but not Fortress. Despite the Age, we have a list of historical figures: Cougars, Blind Cave Ogres, Trolls, and other folks that aren't civilized entities wandering around, along with the FBs. An adventurer can ONLY be started as a Human Outsider.
Test 15: Two civs with playable required, 13 unreasonably aggressive titans. Repeated 3 times.
Result 1: A long and glorious gen, but Age of myth all the same. I seem to have gotten double dwarves, and they seem to be no good at monster killing
Result 2: I got humans this time, but the world still remained in the Age of Myth
Result 3: Dwarves in a perpetual Age of Myth.
Test 16: Bumped titans down to 3 in the hopes that sheer dumb luck would make more of a difference. Repeated 3 times.
Result 1: The Age of Three Powers (Goblins)
Result 2: All three powers died, Age of the Elf with 23 living units. Playable in all game modes
Result 3: The Age of Three Powers (Humans). Titans seem to only meet their match at the hands of hyper-experienced elves regularly
Test 17: one titan, one civ. WHO WILL WIN? (repeated)
Result 1: The Dwarven Age: After 7,000 years, the little guys finally lucked out.
Result 2: Age of the Forest Titan
Result 3: Age of the Hill Titan
Test 18: As above, but 2 civs. Repeated 10 times
Result 1 (goblins): Age of the Hill Titan
Result 2 (Dwarves only): The Hill-Titan Age
Result 3 (Humans): Age of the Mountain Titan
Result 4 (Elves): The Elven Age. They made short work of the titan...
Result 5 (Elves): The Age of Elves. Less short work of the titan, but still...
Result 6 (Elves): The Age of the Elf. Took them a few thousand years this time
Result 7 (Goblins): the Age of the Goblin. They beat that titan almost as fast as result 4 elves.
Result 8 (Dwarves only): The Age of Dungda. I'm not sure what Dungda is, but it ruled the world for ever.
Result 9 (Elves): The Elven Age. About like Result 6
Result 10 (Dwarves): The Age of Meban, and the fewest total historical figures/fastest worldgen in this run
So, what did we learn?
We learned that Elves are the best at killing megabeasts. Every time they showed as the second civ, the monsters of the world died. Unfortunately, that just ushers in the Age of the Elf.
We learned that Humans do not usher in the Age of Man or anything like that, but rather the Age of Twilight, Fairy Tales, or Civilization depending on the world around them -- having humans present in worldgen seems like it might be a good thing for the Age of Death.
We learned that an unopposed Civ won't "finally die" even if the last of its members died -- at least not if it's the only world-gen civ -- the Age it triggered by existing alone is not changed.
We learned you can get a playable-in-adventurer Age of Death by genning a world with Civs: 0 and no megabeasts of any kind. This would probably be Not Entertaining
So, what do we do?
Unless anyone has any bright ideas, we may be out of luck for creating the Age of Death with no modding whatsoever. The question now becomes how far we have to mod to generate the age. Here are some ideas if anyone (perhaps with more modding experience) wants to test them before I get around to it
1) Give all sentients Sudden Kobold Death Syndrome (unable to self-feed). Gen a world with a disgusting number of civs (50-100 on a pocket world) and a few titans. Run this a few times. In experiments before this thread, I found that a huge overflow of civs and unreasonable aggression killed the titans really fast -- possibly before year 4. Hopefully, all civs dying at once will make it recognize Age of Death
2) Same, but no titan, to see if we NEED to start with a Beast
3) Staggered max lifespan on creatures, so humans die last but do die out -- perhaps they will be better recognized as "dead" due to their age progression. No megas to worry about.