The Mature rating is justified by the ESRB for ”Blood and Gore, Intense Violence, Sexual Themes, Use of Alcohol”, as the Skyrim entry describes, ”As players traverse through mountainous open-world environments, they complete missions and quests that impact the eventual fate of their character. Players use swords, bows and arrows, axes, and magic attacks (e.g., fireballs, ice shards) to kill various enemies (e.g., wolves, dragons, human bandits and soldiers).”
“As players engage in melee-style combat, some sequences are highlighted by slow-motion effects, particularly for decapitations. Large blood-splatter effects also occur during combat, and some environments are stained with blood or body parts (e.g., heads impaled on spikes).”
Bethesda Softworks seems to have enough confidence in the game’s selling strength that it is willing to risk a segment of the gamer population being denied purchase of the game. The outstanding sales of The Elder Scrolls IV: Oblivion probably proved that the M rating was not a barrier.