He's rather big for an 8 year old. His occupation was to look over his family's child. As an old model robot his response and speech functions are outdated, causing him to constantly question others comments. He seems to have lost his memory of his family,

Spoiler

so that his family wouldn't have to pay a fee, they illegally abandoned him when they got a newer model. In order to save their personal information they wiped his memory banks. The only memory of them he has is a picture of him that the child he looked after drew, in which he is given his name.