Man, Regulus is one of those characters who makes me want to dig through every dusty prop in the 'Harry Potter' universe. For me, the big items that fan theories orbit are the locket itself (the Horcrux), the note signed R.A.B., Kreacher as a living heirloom, 12 Grimmauld Place, and the Black family tapestry. Canon gives us the locket-and-note combo: Regulus pulled the Horcrux out of Voldemort’s cave, swapped it for a fake, and left a letter. Fans have run with that—some say the note was more than a signature, that it contained hidden cipher clues pointing to where he stashed other items or the method he used. I used to re-read the cave scene and think about smells and coppery potion residue; it’s easy to imagine he carried a tiny tool kit or a protective amulet when he went.
Kreacher is treated like an object in a lot of theories—people trace memories and house-elf obedience as a kind of living evidence chain. Fans imagine hidden compartments inside family heirlooms at 12 Grimmauld Place where Regulus might have concealed other things: a signet ring, a locket box, or even a potion vial from the cave. The tapestry is another favorite; some theorists claim the way the genealogy is stitched could hide coordinates or altered names (like an embroidered clue to R.A.B.’s real motives). Then there are the wilder ones: that Regulus might have had interaction with other artifacts—maybe he saw traces of the ring in some memory or briefly handled something later identified as a Horcrux.
I like these theories because they treat objects as storytelling breadcrumbs. When I picture tracing Regulus’s steps, I think of unpolished brass, ink-stained notes, and a house-elf holding onto secrets—and that mood is what keeps me poking through fan maps and headcanons late into the night.