The Abyss of Time was totally made by the SEES members' personae over six months, it also facilitates time travel. That is practically half of the plot of The Answer.
Personae are in the end just tamed shadows, only much much stronger. Their properties do not change so significantly in becoming personae.
Time travel is coincidentally one of the two things I am explicitly banned from doing, the other being any form of in combat teleportation.
I personally set limits on time space fuckery as well, it takes long stretches of time and uninterrupted concentration to do anything with it, like hours and days. Which is likely the reason there are so few other stipulations on it, there is no practical way to make significant use of it after the game started, it takes too long to get useful results.
That being said, I would like to know if Almighty, the damage attribute with the property of doing damage to everything, would affect your shadow bird. I ask partly out of base curiosity.