User blog comment:Corny4life/the cage./@comment-27669262-20160129211359/@comment-27669262-20160130010110

4 rings should be located somewhere with Winchesters. It would have been stupid to leave this significant and powerful artifact on the battlefield between Michael and Lucifer.

I thought that Death`s ring was active anyway, but i assume you are right that his ring is destroyed because of his death.