Wonder if the amnesia's permanent. Probably not, probably just establishing momentary mind wipe as a measure that the sword doesn't have the established power level it once had...
But yeah, this puts into question a lot of things. And now the image of the sword looking like some demonic cursed artifact. Wonder if she was just using cursed powers when she was living, or if her ongoing torture as a spirit just warped her and she's using demonic forces but is unaware of that and just thinking that it's still holy in nature.
Or if none of that matters and things will just alter for the purpose of the comedy.