[quote=@Hierophant]
That's not possible - Anubis' mantle wouldn't regrow, since he already gave it to you. It would be plausible for an apprentice to take the mantle from his master's dead body. 
[/quote]

I'm totally fine with that, but the document says it regrows.

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If a soul loses its mantle, its power level will decrease slightly, and it may lose some of its abilities, though its potential is not affected. It will quickly grow another mantle, and can eventually recover to something comparable to its original state. It is hence possible for a soul to give out multiple “copies” of its mantle, though the drawbacks mean that such a thing is rarely done. Additionally, each subsequent “copy” of the mantle will be somewhat different from the soul’s previous one, due to the soul’s new experiences since losing its previous mantle; what is lost cannot be precisely regained.

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