Primariluy, what we once knew was that claymore were created from the tissue and flesh of yoma, shape shifting demons that craved human flesh and could perfectly imitate humans and hide amongst them. Somehow, however, Claymore are also far more powerful than yoma, naturally having superior abilities to them in most ways. However, if the Claymore lost control of her yoma side, she would turn into an awakened, which is an even more powrful version of yoma, or so was said.
However, as many fans know now, the Yoma are not what they seem. It is revealed that the yoma are in fact parasites, monsters that invade a host's body and take control. This changed everything. Yoma infected humans and hacked into their minds, pupetting the body and accessing the host's memories, allowing all but perfect replication. However yoma will eventually where out the host body, forcing them to take over another on occassion. This further supported the false belief yoma could shape shift. Not only that, it also shows that the fear people had of people who were near a revealed yoma long enough might turn into one disturbingly founded, as it is possible the yoma could have avoided its death and possessed another.
However, this now throws into doubt what exactly the Claymores are. from what is shown, the yomas are not the creatures forms shown, but the form hidden. It is thus extremely unlikely that the tissue of the host bodies could be used in any process. However, it might show something far more unnerving about the claymores.
Ny the logic of what a yoma is, the question of what exactly is implanted inside of a claymore must be adressed. The theory, i propose, is that what is implanted is in fact a refined version of the yoma parasite. Perhaps requiring reworking yoma remains that have gestated in human hosts, which owuld partly explain the raw need for infecting humans to begin with, it may be that a new creature is born. Instead of a parasite, we have a symbiote. Technically, becoming a claymore has few if any adverse affects for the claymore itself, aside for parts mentally and physically scarring. the symbiote simply sits inside of the claymore, awaiting mental commands from the host in order ot transfer energy or repair damage. however it remains in a partly unfused state, rooted yet not one with the host. however, when the host goes past its limits, they lose control of the symbiote and it fully merges with their being, becoming an awakened. while iti s techncially an enormous benefit for the host in a physical way, the side effect of the merger causes the mind of the host to act much like how a yoma does. however, unlike a yoma, the awakened retain some amount of who they were before the yoma insanity took hold, memories or personality quirks, ableit twisted and warped. ultimately, however, it is unknown if the host of the symbiote truly needs to feed on human flesh, or if it is a reaction of the further icnreased merger.
this leads to two things in canon of the story to be questioned or acknowledged. perhaps miria, deneve, helen, and clare somehow, when they went pass their limits adn returned, somehow managed to communicate with their symbiotes that they did not want ot awaken and managed to retake control of them. if the powers of a claymore have this creature as the core of their abilities, it is not implausible.
secondly, we wold have to abandon the assumption that clare really is one quarter yoma. the theory itself states that the tissue imlanted is in fact a refined parasite, and thus the warriors are not half breeds, but simply enhanced variation of yoma. which may mean that when clare was implanted with 'teresa's flesh and blood' it could mean that the organization recovered teresa's body, dissected it and imlanted the otherwise undamaged sumbiote inside of clare, hoping the girl would exhibit the same or at least similar level of power. howver, while the symbiote obviosuly became active again, it had already bonded with a different host, so the connection between itself and clare is flawed and incomplete. this could also answer to the isntances of clare exhibiting enormous amounts of power, in particular when she awakened her limbs, allowing her to unleash speed and strength far greater than an old, experienced, and highly skilled awakened that not onyl trounced far more powerful claymore than clare herself, but had managed to survive a fight agaisnt not only isley, an abyssal one, but priscilla, if only because of isley's interference.
this idea can also pass over to the ressurrected number ones, whom became abyssal afterwards. what all of them had in common might be that their symbiotes were undamaged. which may explain why the violently mutilated cassandra was selected for the experiment over a number one with less wounded corpse. priscilla's hand was used to create some kind of either drug or compund that caused the symbiotes to come back to life, and thus start repairing the body and bring the host back to life.
at least that is my theory for it all. i actually hope iti s the truth, because it would open a lot more options and perhaps more drama. how would the claymore react knowing that a wriggling mass of yoki sat inside of their torsos.