Hmmm...
with the dimension part, tgat will be interesting
cause its the dimension of the summon spirits
so there will be multiple places and at the same time it can be everywhere ( when a spirit is summoned)

So mary needs to cut blade in order to find his artifact
meaning then when he finds them and they enter into his body
then mary cant find them or blade with her sword
so she can never realize blade got a new one until he uses it
some work by exiting the body while remaining part of it xd