In Chapter 1030, Law and Kid both made an attack on Big Mom and, though Kid’s attack had a visible, massive effect, there was little more than a small amount of blood from Law. Both of these were from peers with awakened devil fruit, so it should be rational their power should be on a similar scale.

What if Law’s attack did more than just give her a sore throat, what if it is still affecting her and will be the thing that actually brings her down in the end?

Law attacked Big Mom by stabbing her with his blade that he specifically mentioned would do no damage but would create shock waves in her body. The location of the Kroom ball on his sword was just inside her neck, centered laterally.

Where he stabbed her, and about as far back up the length of the blade as was the Kroom, you would expect to be in range of the Thyroid gland.

The Thyroid gland is responsible for your digestive function, brain development, and bone function as well as controlling the metabolic rate of the heart and muscles. The Thyroid gets the instructions to operate from hormones created by the Pituitary Gland which is itself responsible for regulating Growth during formative years. Can you name one of these that doesn’t appear to have been dramatically different from the norm in Big Mom’s Normal state.

Breaking that down, here’s how I see Big Mom’s base state:

– Pituitary Gland is overactive causing Gigantism (a real condition though not as pronounced as in One Piece).

– The defective gland in turn creates too much thyroid-stimulating hormone and causes the Thyroid to overproduce the hormones responsible for making her bones strong, muscles powerful, and digestive system hungry as well as under producing the ones responsible for brain development.

– Big Mom starts growing Very rapidly and has an insatiable hunger as well as powerful violent outbursts which forces her parents to find her a new home.

– Her poor brain development leaves her in a child-like state for her whole life while she continues to grow and become stronger!

Law, being a Doctor, knows that this is probably a major reason she is so large and powerful and decides the best course of action is to disrupt her current hormonal balance. Remember he has some experience dealing with Gigantism from Punk Hazard so would be prepared to know how to best destabilize her. He stabs her and uses the shock waves to either lightly damage the Thyroid or disrupt the intake or output of hormones.

The hormones already produced are still in her blood stream and circulating through her body so the effect shouldn’t be immediate but should be pretty rapid once they start to deplete. Her systems will start to fail with her heart growing weaker and slower, her muscles weakening, and digestion disrupted. Depending on the severity, it may be enough to take her down, but I believe it will just bring her down low enough to allow Kid and Law to have a chance of finishing her.

Theory by Squillis (