>>715495970
Because Japanese hell isn't fire and brimstone like Western hell, and traditional Akuma are creatures wreathed in fire, with burning heads and carrying a sword.
Also Akuma are supposed to be bringers of misfortune, which is why Satan got translated as Akuma.
Lives in fire, wreathed in fire, carries an implement to cause pain, and dooms people just by his very existence?
Satan sounds more like an Akuma than an Oni.

Did that make it make sense?