2 main quests ??

[Rui Arrojado]

i only have done till now the companions and the thifes guild, goind for dark brotherwood but is there 2 main quests or 2 ways of finish the game ??

 

[Touchstone]

Companions, thieves guild, etc. are factions.

There is one main quest, but (like everything in this game) it is optional. The game doesn't end.