How about a new disorder for your sanity drain for Shadow, Sword & Spell?
Your character has to have everything that isn’t nailed down. Maybe it’s from a secret greed. Maybe it’s because you now have a compulsion to get things to keep that evil things away. Only you know. Now, when in the presence of objects that are clearly not your, the GM may ask for a Will test, with a -1 TN for the number of times per day you have succeeded at the roll. If you fail the test, you must take the item the GM asks you to take as you now have a secret compulsion to get the item. You have one day to get the item. If you do not get the item in that day you suffer -1 to all tests until you get that item. Taking whatever item may result in extra problems for you and your companions.