HEAD CANON : “ a long blade of the color of blood , upon which has been bestowed the name isshin. it is remarkably sharp and vividly ominous. it is said that this blade can easily cleave through a porous bamboo basket and the water within it before the latter can even leak out. ” on kagotsurube isshin aka the cursed blade / the haunted sword / the bane of kaedehara kazuha’s existence.
because kazuha’s sq was over a year ago now ( and probably boring if you weren’t obsessed and starving for kazuha lore drops like me ) i’ll summarize the canon background of kagotsurube: following kunikuzushi’s manipulation , bladesmith akame kanenaga flees from inazuma to snezhnaya — and crafts kagotsurube upon hearing how the isshin art began to dwindle out as a result. a blade forged using the tatarigami energy and RETAINING IT’S OWN CONSCIOUSNESS , it was supposed to be the weapon to restore honor to both the kaedehara clan and the isshin art , however became corrupted by the same energy it was born of. kagotsurube’s sworn mission then became twisted into PROVING ITS WORTH AGAINST THE GODS. after the death of kanenaga , kagotsurube begins to possess and use people in order to return to inazuma and execute it’s plans. it has led a long life (?) and exhausted much of it’s power by the time it encounters kaedehara kazuha , who allows the blade to possess him AND REFORGE ITSELF back to it’s original power. following the sq , it is implied that kagotsurube isshin no longer has a consciousness of its own : my portrayal is canon divergent in this aspect. kazuha holds on to the sword and uses it as his primary weapon — and it is still very much alive.
while the blade stood by its word in only possessing kazuha for the purposes of reforging itself , and nothing more , he does not trust it entirely. if KAGOTSURUBE IS PLAYING THE LONG GAME in gaining his trust and waiting for the right scenario to play out in which it can enact it’s corrupted goals . . . kazuha would not be entirely surprised by the fact. he is very careful with it : it begrudgingly warms up to the idea of him as a master and allows him access to some of it’s knowledge on the ancient isshin art so that he might instead help it in fulfilling ITS ORIGINAL PURPOSE. however — kazuha only takes enough understanding from this to slightly alter kagotsurube and subdue the abilities that are known to him at the time. it can talk to people only telepathically and still cannot possess anyone unless it makes physical contact. in allowing the sword to keep it’s conscious and make requests of him , this is kazuha’s compromise.
kagotsurube DOES NOT LIKE THIS TURN OF EVENTS one bit. it feels slighted / / deceived by kazuha and is generally rather petty about being kept on such a tight leash , which only confirms to kazuha that he probably did the right thing. whether it is a good idea for him to be IN CONSTANT CONTACT with something forged ( albeit originally ) with tatarigami is lost on him but a risk he is willing to take.
kazuha did consider the proposition of restoring the isshin arts together with kagotsurube — he had been content NOT TO DWELL ON THE PAST long before he ever happened upon the blade , he dubiously turned down the tri-commissions offer to help him reform the state of the kaedehara clan , and he would never have posed any of these questions to himself had he not happened upon the traveler and discovered kagotsurube that day. however . . . having the knowledge he required to make accomplishing those things an actual possibility OFFERED TO HIM SO EASILY made him falter and very genuinely reflect on what he wanted. it was different , then , to the old notion of making any attempts to clear the shame of his family with no real support at his disposal. in the end he still decides to trust his instincts and leave the past where it belongs. when he lets the blade open up that information to him , he takes only what is needed to amend it slightly so that the temptation to change his mind IS REMOVED entirely.
after being tricked , kagotsurube is not as big of a fan of kazuha as before. they bicker. it withholds the knowledge of it’s own abilities from him and sometimes , throws them out mid-combat to test his worth. kazuha genuinely does not know the full scope of kagotsurube as a weapon —- but he accepts what it shares with him AS A CHALLENGE TO ACCEPT even when it does so to oust him for fun.
kagotsurube likes powerful people very much. if they are around someone it senses any sort of affinity to , it hounds kazuha ( and them ) endlessly to let them wield it instead. JUST FOR FUN. noting the tatarigami energy around tomo and his apparent resistance to it , it is especially obsessed with the idea of being passed on to him instead of kazuha — but it will still hassle anybody it takes a liking to.
