creepypasta origin

Chara

After falling into the Underground, Chara was taken in by Toriel and Asgore as a second child and was treated with respect equal to their biological son. Chara and Asriel became best friends, and monstersspoke of how Chara filled the Underground with hope.

One day, after becoming terminally ill from consuming buttercups, Chara expressed the desire to see the Golden Flowers found in their home village. After their death, Chara's SOUL was absorbed by Asriel, and they shared control over a body. Chara carried their own corpse across the barrier and wanted to use their full power. Asriel resisted Chara, which ultimately led to the humans killing the fusion of the two SOULs.

Chara's motives in this situation are uncertain. In the fourth True Lab tape, Asriel says "Y...yeah! We'll be strong! We'll free everyone.", and in the fifth "Six, right? We just have to get six..." In the Genocide Route, Flowey tells Chara that they should finish what they started and free everyone. Flowey also adds, "Then... let's let them see what humanity is REALLY like. That despite it all... This world is still 'kill or be killed!!". Asriel tells the protagonist that he came up with this philosophy because his resistance to Chara had led to both of them being killed. At the end of the Genocide Route, Chara says little about Asriel's resistance other than, "At first, I was so confused. Our plan had failed, hadn't it?"

Chara's body was originally laid to rest in a coffin in the basement of the castle, where the bodies of the other fallen humans would later be put. When she left Asgore, Toriel carried Chara's body to the Ruins and gave them a proper burial.

In the Genocide Route, Chara says that the protagonist's "determination" and "human soul" awakened them from death. There is evidence that some narration, as well as descriptions of certain actions and events, is by Chara themself. However, the narrator throughout the entirety of Undertale is up to speculation.