Sango is a demon exterminator and has been trained in the art of killing demons from a very young age. She is the daughter of the chief of Taijiya village; a town that earned it's living by exterminating demons that attacked other villages and the surrounding countryside. Letting nothing go to waste, the village collected the bones, hides, shells of the demons they defeated to make their weapons and armor, including Sango's gigantic boomerang Hiraikotsu.
One day a local lord called for the village's best exterminators to come to his castle and exterminate a demon that had been attacking every night. Sango's father went, along with Sango, her little brother Kohaku, and two other exterminators. They easily defeat the spider demon, but Sango senses that something isn't quite right. Sure enough, Naraku, who has been masquerading as young lord Kagewaki, takes control of Kohaku. Kohaku turns on his companions, quickly killing his father and the other two exterminators in the confusion. Kohaku then turns on Sango, but she blocks his kusari-gama - heavy-bladed sickle on the end of a long chain. Sango sees the web attached to Kohaku that's being used to control him and follows it back to the lord of the castle. She charges the lord in an attempt to free her brother, but Kohaku hits her in the back with his kusari, stopping her charge. Naraku releases his control over Kohaku, who realizing what he's done runs to help Sango. The lord orders his guards to shoot the two. Kohaku is hit with multiple arrows and falls to the ground. The wounded Sango shields him from further arrows and finally collapses as well.
Just then, Naraku masquerading as Kagewaki kills the lord and says that it wasn't really his father; it was the spider demon in disguise. He then orders that the demon exterminators are to be properly buried in the castle. Miraculously, Sango survives and digs herself out of her grave. She is found by Naraku/Kagewaki and has her wounds tended. While Sango is recovering, Naraku uses one of his puppets to tell himself that Taijiya village has been wiped out by Inuyasha and the village's Shikon jewel shards stolen while, making sure that Sango can overhear. Devastated, Sango demands her weapons and armor in order to avenge her family and village. Being the great guy he is, Naraku gives her a Shikon jewel shard so she can fight without feeling pain from her wounds. Not heal them or anything mind you, just blank out the pain.
Despite Inuyasha and the gang's wishes, Sango attacks and is quickly defeated despite Naraku helping in the form of his wasps. The wasps grab the Shikon jewel shard and beat feet, causing Sango to pass out from pain and blood loss. Kagome tends her wounds and she regains consciousness to find that Inuyasha and the gang had already paid proper respects to the villagers. She learns that Naraku was the one behind the whole thing and she decides to join the group to exact revenge and free Kohaku, who she learns has become one of Naraku's puppets.
