To my knowledge, there's never been any publically stated drop rates for HSR - so even trying to guess its rarity would be difficult, lest comparing it to other hero items.
To be it in perspective, I had T4 luck on for 1.5 billion combat XP (and 200m slayer) with 50k boss kills, and never even saw a blueberry special (1/10 chance of HSR). I recon I've killed way over 1.5million monsters on the RDT. For the seren spirit - probably a 1bill xp, and seen two vecna skulls, no blueberry's.
Long/short - its fooking rare.
27-Feb-2021 05:33:56