You should have acted. They're already here. The Elder Scrolls told of their return. Their defeat was merely delay until the time after Oblivion opened, when the sons of Skyrim would spill their own blood. But... there is one they fear. In their tongue he is Dovahkiin; Dragon Born!
The assassins in the base game are weak. I searched for a mod which could improve them, but didnt find any, so I made this plugin. This mod increases the assassins to 20, one for each gender and race, and gives perks to them, lining them up to OBIS standards.