Elder Scrolls IV: Oblivion is one of the many games in the Elder Scrolls series created by Bethesda in 2006. It is also the Elder Scroll created before the famous Skyrim and just like all the other ones before it, Oblivion is another open-world RPG game.
In the beginning of the game after choosing and designing your main character you start off in the dungeons for committing an unknown crime. You get out when Emperor Uriel Septim VII and his bodyguards have to use your cell to flee from assassin’s targeting him. After you and the group is about to get out the Emperor gets killed and before he dies he entrusts you with the Amulet of Kings, typically worn by the emperor, to take it to Jauffre, Grandmaster of the Blades.
You later find out you have to find and help the lost, and last, son of the Emperor become the new emperor. Along the way you find out that barriers to Oblivion, their version of Hell, are opening up all around Cyrodiil and you are the only one that knows how to close them.
But you know that Oblivion isn’t an Elder Scrolls game without its guilds. There is the Arena, where you can fight to be the ultimate champion. The Dark Brotherhood, where you can sharpen your sneakiness by becoming an assassin. The Mages Guild and the Fighters Guild which is pretty self-explanatory. And lastly there is the Thieves Guild were you can master the skills of a thief.
Arena 
Dark Brotherhood 
Mages Guild 
Fighters Guild 
Thieves Guild
But don’t forget that Oblivion is also an open world, so you can explore all the towns, cave, hideouts, and cities of Cyrodiil for as long as you please. It’s not like the world will slowly get taken over by Oblivion in the meantime, your main character.
Oblivion is available for Playstation 3, Xbox 360, and the PC.