Rhyme's Talisman

"This isn't mine, and someday I'll return it. but for now, I still need it."

And old and worn adventuring bag that Rhyme's partner gave him when they were kids. He doesn't acknowledge that he has been given ownership of it and still regards it as being borrowed. It's torn in places and has needed many repairs over the years, but Rhyme is intent on keeping it (mostly) safe until the day he can give it back.