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Tear Jerker: RuneScape
During the Fremennik Saga, Vengeance we get a Perspective Flip from a typical dungeon in Daemonheim, as one of the people that the "heroes" fight as she tries to take her vengeance on the people who killed her little brother. Throughout the Saga, you come across the Forgotten Warrior's friends and family. And they all have unique examine texts, like "She was about to retire," "He knew more dirty jokes than anyone," and "He could out-drink anyone." And that's when you realize exactly how many of these people that you've killed in proportion to your Dungeoneering level. It quickly becomesNightmare Fuel as the story goes on.
At the end of the quest A Void Dance, the player defeats the boss and found the "culprit" of the mysterious plague, a pest used by the black knights for its live-draining abilities. While killing it is the best way to prevent it from being used again, the music is determined to scar you for life.
The quest after that isn't any better. The player is placed into a position where either Korasi or her friend are taken hostage for confronting Grayzag and must decide who gets to live while the other's life force is used for the queen. There is no third option.
The fate of the dragon riders. They were a humanoid race from another dimension that lived in complete harmony with wildlife surrounding them, but were seemingly cursed with infertility. As their numbers slowly died out, Zaros appeared to them, and offered them the chance to give birth again if their served him in the God Wars. They accepted and followed him into Gielinor, but no matter how loyal they were, Zaros refused to grant them their fertility again until he won the war. Their numbers began to dwindle even faster now, thanks to the casualties they were suffering, until only five remained. Two of them were fed up with the lie Zaros had fed them, and wanted to side with Zamorak, while two wanted to remain loyal, and the last was indifferent, believing that they should sit back and just side with the winner. They argued for quite a while, up until the point where Zaros was finally banished, and Zamorak had won. Unfortunately, all of Zamorak's warriors believed the dragon riders were still loyal to Zaros, and all of Zaros's warriors believed that the dragon riders had abandoned them when they needed them most, so the remaining five are all hunted down and killed, one by one (and in gruesome detail), until only one remains. The last dragon rider flees into a cave deep until the wilderness, and spends his last days alone with his mount (The King Black Dragon), writing down the fate of his people before he wastes away.
It might not be so bad. One of the recent future update hints involves a television character named Hannibal. The most relevant Runescape character to that is Hannibus, the aforementioned last Dragon Rider, so he might still be alive and appearing in a quest where Zaros gets his body back.
Partially confirmed. In a February 2014 Grandmaster Quest, Hannibus will indeed be appearing as the Last of His Kind. Zaros won't be involved, but the quest will involve the player helping Hannibus adjust to the world.
The fate of the first wizard tower. Originally it was fully integrated and incorporated wizards who were aligned with all the gods, but a particularly bad instance of Poor Communication Kills left only two people remaining, one of whom eventually destroyed the first wizard's tower.
The backstory and death of Guthix. He was the last survivor of a god war on another world, and sought to make a peaceful society with no godly intervention. However, given that by this point he had become a god himself, it was doomed to failure. And then new god wars started, ruining the perfect Gielinor forever. By the end, he does nothing to prevent his own death, despite being perfectly capable of it.
Extra mention should be given to how the only casualties we see are farmers, craftsmen, and Guthix's friends and family. The only warrior in that entire area belonged to, and was created by, a god.
Guthix wanted to see his family again when he died. In a later quest, Death reveals that when a mortal becomes a god, they give up the ability to go to the afterlife. Instead, their energy is scattered throughout the world.
In addition, the music track that is unlocked during your voyage through the memories of Guthix is a very melancholy tune that further compounds the sadness of the event
From that very same quest, if you side with either the Guthix or Saradomist sides, Azzanadra's reaction is quite jarring. Despite his intense loyalty to Zaros, so intense that that's why he became borderline immortal, Azzanadra is visibly saddened at the thought of fighting you. After witnessing the Puny Earthling attitudes that many other Mahjarrat have towards humans, the thought that one of them considered you a friend was touching. And then you betray him.
In the dwarf quests, you already knew that Colonel Grimmson had likely been brainwashed into joining the Red Axe after he'd been detained by Veldaban following the defeat of the trolls at Barendir. Turns out that when he went berserk at Barendir, Grimmson had accidently cut down a dwarf (possibly more). This caused him to enter a Heroic BSOD, which led to him letting the Ogre Shaman mess with his mind so that he could sleep at night. During the final confrontation, Grimmson is offered the chance to go back, and replies that he can't go back, he is the "butcher of Barendir", and wants to die a warrior's death at Veldaban's hand like he should have back then.
When King Bolren describes the loss of his wife and children in the quest Tree Gnome Village.
The end of One of a Kind. Kerapac offers to cure Hannibus of his infertility, but there is no guarantee, and it will require decades of Hannibus being in stasis (did I mention he's been Taken for Granite since the Second Age?). While taking a walk outside to consider, Hannibus is approached by the White Dragon from earlier in the quest who went to his home world and brought him his grandchild. It turns out the remnant of the Dragon Rider race is preparing for extinction in a vaguely Circle of Life way, and is guiding the creatures of their world so that another will become the soul of their world. The player must decide whether Hannibus should accept Kerapac's offer, or be with his family.
For years, one type of high level ranging armor says it is made from White Dragonhide, which at the time didn't exist outside of finding that armor in a Treasure trail. Some players speculated about introducing white dragons so they could be killed. Be Careful What You Wish For. One of a Kind revealed that only one, Therragorn, is left. The others were either killed to make armor (which is why some players wanted them introduced), or were experimented on by Kerapac to create Celestial Dragons. The process was apparently painful. Made far worse when you realize that unlike every other dragon species, the White Dragons were not vicious monsters.