Then install this mod by using "daupdater" or "DAO-Modmanager" or whatever you familiar with.
LATEST UPDATE _There will be a chest spawned inside the revered mother's room in Lothering Chantry. Take the items from that chest.
_For those who already made it out of Lothering and can't go back there, type runscript kossith_armory in the console to retrieve the items. (Download the Missing_Script first)
Sten Sword: Note that it does not override the original Asala. This is an entirely new weapon. And it's not a great sword, it is a long sword. So, you can equip two of them on Sten if he has the "dual wielding" skill. You can still have the original Asala (Great Sword) if you give Sten the gift.