"Sorry, am dumb..."Boy is a serf that has been commanded by the Emperor to manage the vox equipment for the Emperor's podcast.
TTS Canon Edit
Boy is very nasally and ignorant of current events, in part due to his illiteracy, and in part due to the Imperium placing little emphasis on educating the common masses. Before working as a voxcast serf, he and his family made money selling greasy food to petitioners in the palace (while getting trampled frequently). However, he has been studying under Rogal Dorn, who has encouraged him to aspire to be more than a mere serf. In fact, he affectionately calls Dorn "Dadorable," after his wall-name of "Lord Adorable."
When asked what his name was, the boy took too long, so in his impatience the Emperor simply had him renamed as "Boy."
Whereas Rogal Dorn has taken to looking after Boy, the Custodes are ambivalent to his needs, especially Karstodes, who finds his presence obnoxious and threatens multiple times to eject him and/or snap his neck.For some reason Boy is terrified of Cyberdong and believes him to be a harbinger of death, probably because of the skull that he wears.
Boy lost one of his eyes when Helbrecht smashed a teacup in his face. Despite this, he was able to perceive horrifying images through his missing eye due to the cursed book Inquisitor. Dorn was deeply troubled by Boy's trauma, but was hopeful that he could grow up to become stronger.
It is wildly speculated by the Fan-base that Dorn is in fact training and molding the young Boy. What he is training Boy to become is unknown and it is thought to be any thing from the next Chapter-Master of the Imperial Fists to the next Emperor of Mankind.