Give the Orc slayer to Leo

Hint: West of Lars Town there is a valley inhabited by dirty and smelly orc.
They are many and the are most eager to make sure that the mighty
Orc Slayer is not let out from their treasury. That weapon is dangerous,
and all orcs know it from childhood.

You are to prove yourself a worthy adventurer, by retrieving the Orc Slayer
from the evil orc shaman, and give it to Leo, the Archwizard.