Oblivion Remastered surprise-launched this week, but less surprising was the game’s Mature ESRB rating. Oblivion wasn’t always rated Mature, however–when the game first launched in 2006, it was released with a Teen rating, which was quickly changed by the ESRB.
After launching with a T rating, the ESRB ratings board had to issue a correction, bumping the rating up to Mature due to “due to the presence of content that was not fully disclosed when the game was originally submitted to ESRB for rating.”