>>280362858
>so much knowledge of the world
She's not particularly knowledgeable outside of everyday chores, dungeons and monsters.
>what was her upbringing
Yes it is explained later in the series. She had normal family but abnormal childhood: since she was wee small kid, she played "catch" with REM golems, giant ass mythril constructs that can smash adult with one hit. Naturally the game was not to get hit. She also defeated NT ants and collected their stingers, then threw them at REM golems until they got poisoned, and then dodged until they collapsed from poison (idk why golems have no poison immunity). Then she grew up, her tits blew up and she started to attract male attention. Some dude started salivating all over her, but he had a fiancee, who was from powerful wolf clan. Essentially, ojou fiancee of that dude ruined Roxanne parents and forced them to sell Roxanne into slavery with "No wolf demi-human owners" to protect her from ojou bitch.

They meet yet again after Roxanne is already under Michio. Ojou issues a duel, Roxanne fucks her up. Patriarch of their wolf clan beheads ojou for dishonor on the spot and demands rematch. Michio deletes his ass and their house essentially disbands because they lost their investment into patriarch wolf.