After finish The Magnus quest line, players can use the inventory of other counties.
But at first I don't know how to do, I jump into the Magnus, and cannot find the inventory!
The right way to use it as follow steps:
1. Go to the inventory guard:
2. Talk to him and open the inventory:
3. Click the label with a name of other county, then you open the inventory of that county:
4. Enjoy the convenient!