Shen Siyuan often saw this umbrella in Duoduo's memories.
Whenever it rained, Duoduo liked to summon the umbrella to shelter from the rain.
It didn't seem particularly special since it's not uncommon for ghosts to possess items.
For instance, Lu Guanchang's walking stick was actually a manifestation of his will, a part of his body.
But this umbrella of Duoduo's was clearly different; it existed independently and could be used by a ghost – it was a Netherworld Artifact.
"Do you know where this umbrella of yours came from?"
"It belonged to my mother," said Duoduo.
"Where did your mother get it from?" Shen Siyuan continued to ask.
Upon hearing this, Duoduo tilted her head, evidently unaware of the specific origins of the umbrella.
Then she unconsciously twisted the handle of the umbrella, and suddenly her figure disappeared from the spot.
This was not invisibility; no spirit that had entered the Ten Thousand Soul Banner could hide their presence from the Banner Master.