I think I know what happened to the Sage's Mom.

[A$AP Wap]

She became the Shinigami for the Reaper Death Seal. They look just alike.

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Ootsutsuki Kaguya

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Shinigami of the Reaper Death Seal

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(Ew, I know. Turned me off too.)

She probably became the reaper after she died because her Spirit was so Powerful.

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- I was told Derp made a theory that resembles this one and he's probably right.

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[Snape Uchiha]

Perhaps, though I hink she is jus supposed to look like a shinigami in general. Also note how it looks like she has a byakugan.

 

[Lucidus]

someone already made a great theory about this.. i think it was SDO that did it.. but yes i agree she is very similar and could very well be the RDS itself

 

[Saikyokami]

Derp said dat when madara told the story v_v

 

[A$AP Wap]

someone already made a great theory about this.. i think it was SDO that did it.. but yes i agree she is very similar and could very well be the RDS itself

Derp said dat when madara told the story v_v

Link me to his thread so I can give him some credit.