Being standalone does not preclude characters from being spiritually reincarnated, much like Patches. I mean, heck, the player character is basically the same archetype as in Dark Souls, so why couldn't other things be related? Now, it's definitely got it's own lore and setting, but the characters feel pretty familiar at times. Also, do remember that Miyazaki left room for the player to make up their own story. So, he could be Bloodborne's version of Nito. Especially if you want him to be. PS: I also think Oedon is the Old One from Demon Souls. Take that how you will. You don't have to agree.