Aventus Aretino is a Nord child in Windhelm found in the home of his deceased parents. When found, he is performing the Black Sacrament, hoping to contact the Dark Brotherhood. Desiring the death of Grelod the Kind for mistreating her charges at Honorall Orphanage, he asks the Last Dragonborn to fulfill the contract. If successful, he gives them the Aretino Family Heirloom.
Aventus lost his mother Naalia when he was about 10 years old; the fate of his father is unknown. Since he had no one else to care for him, Jarl Ulfric Stormcloak sent him to Riften to live at the Honorhall Orphanage. At the orphanage, he developed a strong hatred for the headmistress Grelod the Kind, who, despite her name, was extremely cruel to him and the other children. Aventus escaped from the orphanage and returned to the now-deserted house in the middle of Windhelm where he had lived with his mother when she was alive. When the Dragonborn encounters him, he is attempting to contact the Dark Brotherhood by performing the Black Sacrament.
In the Dragonborn's travels a rumor is heard about a child in Windhelm that is trying to contact the Dark Brotherhood. This rumor can be heard from multiple sources, including innkeepers and guards. Upon hearing this rumor, the miscellaneous quest, "Talk to Aventus Aretino" begins. Upon reaching the Aretino Residence, a child, Grimvar Cruel-Sea, can be seen asking Idesa Sadri if it's true that Aventus is trying to perform the Black Sacrament. Idesa tells him that this is nonsense, but when Grimvar says that he's going to go ask Aventus to play she quickly hurries him away.
Upon entering the house, the Dragonborn finds a macabre scene, as the Aretino boy chants the prayer to the Night Mother over and over while stabbing an effigy made up of human parts. If the Dragonborn waits it becomes chillingly apparent that the boy has been performing the ritual for a great deal of time; but undaunted he continues to stab his home-made effigy of Grelod, as he pleads for the Night Mother's help. No matter what is said, Aventus is sure that the Dragonborn has come to fulfill the contract if he is spoken to, and the quest Innocence Lost begins.
- "When I grow up, I'm gonna be an Assassin, that way I can help lots of children, Just like you!"
- "Really, I mean, I knew the Dark Brotherhood was good... just not that good! You killed the old hag before I even asked!" (if Grelod is killed before talking to him)
- "I'll go back to the Orphanage in a while. I'll give them time to, you know... clean up the mess."
- "Sweet mother, sweet mother, send your child unto me for the sins of the unworthy must be baptized in blood and fear." (repeatedly, until the Dragonborn interacts with him)
- "I'm so tired..." (between bouts of praying and stabbing)
- "You came to visit! So much better now that Grelod's gone, thanks to you!" (this one only appears if another Aretino spawns in the orphanage)
- "No! It's not supposed to work like that!" (if the Dragonborn attacks him before talking to him.)
- Despite being Nord, Aventus is sometimes referred to as Imperial by others.