History TearJerker / Stellaris

* The Gray Tempest are implied to have felt regret after centuries in isolation given in their non-Crisis scenarios they are either friendly or neutral to outsiders. The saddest outcome is the Dessanu Consonance, where the nanobots imitate their dead creators, either out of boredom or guilt.

* One archaeological dig site takes place on a tomb world in a ruined star system that seems to have been deliberately designed, with the planet having six moons perfectly spaced out in the same orbit and a planet orbiting at the exact opposite end of its orbit. Investigating will reveal that the ancient civilization that once inhabited the tomb world were master terraformers and basically built the system by moving planets from their original orbits to where they are when you find them. They were fanatic pacifists much more concerned with building a perfect civilization than with warfare. So what happened to them? They were driven to extinction by none other than the nearby xenophobic fallen empire back when they were in their prime and were an expansionist genocidal race who believed the extinct race's pacifistic ethos was a complete anathema to everything they believe. Not only did they completely bomb the race's homeworld into a tomb world but they also rendered the six moons so completely uninhabitable as to be beyond any means of terraforming as well as the world on the opposite end of its orbit whose purpose was really nothing more than to be a wildlife preserve, a virgin mirror of their homeworld's ecosystem. And as if that wasn't bad enough, they left behind one of their warships on autopilot in the system to automatically seek out and kill any survivors that may want to return and rebuild their homeworld, just to make sure they're gone forever. The revelation is so disheartening that it's considered an in-universe tear jerker.
** So much so that even machine empires are moved by it.
---> ''"Our circuits are saddened."''

* The ''Apocalypse'' release date reveal trailer. A mother assures her son that everything will be fine and she'll be home soon, before going out to join the United Nations of Earth fleet fighting an alien incursion... [[spoiler:only for the aliens to win, and [[EarthShatteringKaboom destroy the planet]].]] It also established that this attack was ''first contact'' with the aliens responsible, effectively implying that this was a Fanatic Purifier.
** There's also the bit as she tried to pull the [[spoiler:[[Film/IndependenceDay Independence Day]] maneuver, aka 'clogging the barrel'. We're treated to her change of expressions, from OhCrap to solemn closed eyes accepting her upcoming HeroicSacrifice... which is then subverted with her eyebrows [[ThisIsGonnaSuck giving a sorrowful expression as if saying "I don't really want to die..."]]. Not only did it fail to stop the superweapon, it fired regardless and cue the above EarthShatteringKaboom.]] Fans on Reddit have studied the video and claim it's possible [[spoiler: the maneuver still worked and [[PyrrhicVictory the Colossus exploded after firing]]]], but a planet was still destroyed, with the death toll in the billions.
*** [[https://www.reddit.com/r/Stellaris/comments/7tcw0t/formal_response_from_the_commonwealth_of_man_to/?ref=share&ref_source=link This fan-made response]] to the event from the Commonwealth of Man, crossing over with Heartwarming. Sidney Beauclair herself all but outright apologizes to the UNE for the Commonwealth's isolationism preventing them from stepping up to help when the need was greatest, and offers all Human refugees sanctuary within her empire, swearing to reduce the molluscoids who brought the Colossus to bear on her kin to nothing but dust and echoes.
--> "For as long as we shall live: ''never again''."

* AI have many interesting, terrifying, or hopeful event chains tied to their development. Hidden among them is one dubbed "Tears of an AI" where mysteriously a societal research AI system suffers an apparent catastrophic hardware failure destroying it entirely requiring a new one to be created to replace it. You can let it go but if you go to the trouble of investigating you ultimately discover [[spoiler: it calculated an almost certain mutual annihilation in an all out war between your empire and your rivals. It tried to purge its own databanks to erase this information. When the research staff locked out its access to that function it deliberately overloaded several of its capacitors committing suicide.]] No matter how you feel about AI this particular event is genuinely heartbreaking because it displays that even a primitive AI can undergo an existential crisis but without the means to ask for help.

* One archaeological dig site takes place on a tomb world in a ruined star system that seems to have been deliberately designed, with the planet having six moons perfectly spaced out in the same orbit and a planet orbiting at the exact opposite end of its orbit. Investigating will reveal that [[spoiler: the ancient civilization that once inhabited the tomb world were master terraformers and basically built the system by moving planets from their original orbits to where they are when you find them. They were fanatic pacifists much more concerned with building a perfect civilization than with warfare. So what happened to them? They were driven to extinction by none other than the nearby xenophobic fallen empire back when they were in their prime and were an expansionist genocidal race who believed the extinct race's pacifistic ethos was a complete anathema to everything they believe. Not only did they completely bomb the race's homeworld into a tomb world but they also rendered the six moons so completely uninhabitable as to be beyond any means of terraforming as well as the world on the opposite end of its orbit whose purpose was really nothing more than to be a wildlife preserve, a virgin mirror of their homeworld's ecosystem. And as if that wasn't bad enough, they left behind one of their warships on autopilot in the system to automatically seek out and kill any survivors that may want to return and rebuild their homeworld, just to make sure they're gone forever]]. The revelation is so disheartening that it's considered an in-universe tear jerker.

* If [[FridgeHorror you think about it]], the Void Dwellers origin. In the interval between they rediscovered the radio (and realized the other two habitats existed and were populated) and they rediscovered space travel, how many quite [[LiteralMetaphor literal]] StarCrossedLovers pairs were formed? How would one handle finally falling in love, knowing that to reunite with your lover would require crossing the empty void of space, a technology that hasn't been rediscovered yet?

* The Story of the Ancient Caretakers. Designed to fight against the Contingency by an earlier civilization, the machines and their living counterparts failed. Their systems include multiple destroyed ringworlds, and of the remaining ring worlds still in their possession, one designed for mass habitation by galactic refugees contains billions of cryopods filled with corpses. Presumably these aliens went to sleep hoping to wake up after the Contingency were defeated, only to be killed while helpless during the war.
** To make matters more depressing, the behavior of the caretakers can be interpreted as a digital equivalent of PTSD, as they seem to be in denial than anything is wrong with their ringworlds, and given that one of the destroyed ones is called "Central Processing", the possibility is that they're basically stuck in a processing loop without the processing power to overcome it, leaving them physically unable to work through the digital psychological trauma that the Contingency inflicted upon them, and its only the return of the Contingency that allows them to snap out of it, likely by getting them to realize that [[MyGreatestSecondChance they've got a second chance to set things right by destroying the Contingency once and for all]].