I just came from there. Wouldn't have discovered this if I didn't saw some post over there. Seems like it is related after reading the 1st chapter. Reincarnation maybe? If that's the case then I can understand his possessiveness of his Sheath when he became the older one.
Is This Temper My Blade? The Past or something else? ;w;
Oh Wait this is probably why his current master(From Temper) is possessive of him