I'm getting a little confused here, maybe it's the translation? The sword is the girl, and the sword is becoming tarnished and rusted, and the Flame Heavenly Demon King (what ridiculous name) is sealed within it. The FHDK is constantly torturing Laen (causing all those status effects to her body on the outside) in the whatever pocket world of the sword, to try and get free, but freedom will only come when the sword is properly wielded by someone of at least level 150. Bridgette says something to the effect of "...She fought alongside us 100 years ago to defeat the 6 HDKs..."; but Bridgette also says she is an "ordinary person", so how can she both be ordinary and strong enough to fight the HDKs? Does this mean that Laen and Bridgette are over 100 years old? They look damn good for their age!😍
Is the body of Laen that is outside the sword just a projection of her spirit? If that is so, why does it have a house, and friends, and etc? Bridgette seems to know that Laen's spirit is suffering horribly inside the sword, and has been for more than 100 years, but is just like "hey let's go find some magic rocks today, body of Laen!". After all this purported time, there doesn't seem to be a sense of urgency, until now, which is just weird.