Source

Most of video games characters are inspirational and strong individuals, or cool yet terrible villain. But behind all things that we see about them on the outside, most of them don't have a wonderful past. The following list is some characters with tragic backstory.

Nautilus (League of Legends)

Source

Nautilus used to be a sailor, until a terrible incident changed his life and who he is. One time, he was sent to explore uncharted reaches of a sea where none of his man aboard are brave enough to investigate. Nautilus was the only one who had the guts to do it. A moment later something mysterious pulled him to the bottom of the ocean. Instead of helping him, his crew fled with the ship and leave him behind. When he woke up, his diver suit fused to his body, it IS his body now. Then he wander around until he stumbled by the shores of Bilgewater, but nothing there for him, people are scared of him. No friends, no family, no home, nothing.

Uncle Leo (Fallout 3)

Source

This one is kinda inspirational. Despite his unfortunate fate, exiled from his super mutant brethren, Uncle Leo embrace the spirit of giving and grace. He recalls his adventures to anyone who are willing to listen, and gladly gives gifts to those in need. That's the reason why he was exiled, because he is 'not a brute'. Other super mutants could not tolerate his message of peace so they cast him out. Uncle Leo has roamed the Capital Wasteland ever since.

Swan (Fallout 4)

Source

Swan's tragic story can be found in several scattered notes around Swan's Pond. His real name was Edgar Swann. Got caught and imprisoned for stealing cigarettes, he agreed to 'probation' and house arrest, where he was unknowingly exposed to an experimental version of the Forced Evolutionary Virus by Institute scientists. Within a week he began to mutate and possesed increased strength and intelligence. However, on the third week he began to have seizures and his intelligence decreased. 

Terra Branford (Final Fantasy VI)

Source

Terra had it tough too. She was born in the Esper World, until two years later Emperor Gestahl of the Gestahlian Empire led an army to raid the land and took her away from her parents, Maduin and Madeline. Gestahl raised Terra as a living weapon for the sole purpose of serving his madness. Soon General Kefka Pallazo place a slave crown on her which not only control her free will, but also destroyed the memories of the better part of her life. 

Sarah Kerrigan (Starcraft)

Source

Sarah Louise Kerrigan's telekinetic power were demonstrated during the incident on TarKossia when she was young, causing terrible accident that killed her mother and damaged her father's brain. She was taken immediately by the Terran government and conscripted as a child into the Ghost Program that eventually turned her into an assassin. She spent her childhood being tortured by Lieutenant Rumm mentally and physically. As an adult she had a relationship with Jim Raynor and joined in a rebellion led by Arcturus Mengsk, only to be betrayed by him because wanted long-due vengeance for the deaths of his family. Later, the Zerg Overmind adopt her and turn her to the Queen of Blades, a fearsome half-Zerg and half-human entity of great power. 

Jack (Mass Effect)

Source

Jack was abducted by Cerberus operatives in 2165 when she was a just a little kid for her biotic potential. Her mother was told that Jack died due to complications of her eezo exposure. Jack live her entire childhood as experimentation subject, Subject Zero. Mental and physical torture is like her bread and butter. Even worse, when she finally escaped the facility she was captured by another ship. The ship's crew 'used' her before selling her as a slave. After that, she live a violent life and become a criminal. Sometime later she was captured and imprisoned in the Blue Suns prison ship. During her time there, she was attacked by a group of guards and prisoners who raped her. 

Pamela Redpath (World of Warcraft)

Source

Pamela and her family lived in Darrowshire and was killed during the Battle of Darrowshire. Her ghosts still linger in the ruins, asking adventurers that meet her to find her doll and eventually avenge her family's death. She says sometimes she hear her father, crying in the distance and wish to tell him that she is okay. I don't know if she understand that she is already dead or not.

Little Sister (BioShock)

Source

Little Sisters are young girls between 5 to 8 years old who have been genetically altered and mentally conditioned to harvest ADAM from corpses around Rapture. In an almost completely ruined city which is not appealing for such young girls, Dr. Yi Suchong has mentally condition them. He made the children to see the world of Rapture in completely different way from reality. Instead of seeing the dark, deteriorated state of the city, they see an idealized child's world, with rosy marble floors, pink or red drapings, and flowering vines growing everywhere. They see their Big Daddies as noble knights, and Big Sisters as princesses with elegant apparel, and the dead bodies of Splicers as "Angels" lying in elegant pose. All the lies that they see is only for the purpose of harvesting ADAM. Sure they look happy when we see them in game, but it's more like they are.. How to put this correctly, tripping(?)

Iris Von Everec (The Witcher 3)

Source

Iris was from a noble family of the von Everec. She was married with Olgierd von Everec. Over time their marriage declined as Olgierd started to no longer have feelings for Iris. One time Iris wished to divorce him so her father began to read over the reasons to Olgierd. However, Olgierd lost his temper during the reading and killed Iris' father, making her lose all feelings for him. Only remembering that he was supposed to love her, he gave Iris the black cat and dog for companionship and a mysterious being known as the Caretaker, although she didn't want any of it. Then he decide that he didn't want to cause her anymore pain, Olgierd left, leaving a letter and a violet rose to remember him. Iris, alone in the estate, laid in bed for days. Staring at the rose until it finally crumbled to dust. And she died soon afterwards. 

Well, not all of them are the hero or the villain. The list above is only some of many other characters with tragic background story.