>>49847025
These are flying yin yangs, not the Yin Yang orbs.
Also check Misumaru's dialogue in UM:
>I can't afford to lose the inheritor
of the Yin-Yang Orb to suffocation.
Sure sounds to me like Reimu is somehow an important figure in regards to the orbs.
>>49846999
I've seen theories like that but I doubt it. Maybe Reimu is the last member of the clan inside Gensokyo, or maybe she's the last member of the clan but not of the bloodline.

Good sanny thread.