Inuyasha made no attempt to block the punch, and went down like a sack of vegetables unceremoniously dropped on the ground. As the hanyou struggled awkwardly to get back up, Sango realized what was going on just before Kagome said it out loud.
"Inuyasha's eyes… he can't see?" That had to be it. There was no other explanation for the sudden change in his behavior.
"Compared to me, you were always worthless," Sesshoumaru told him, goading him on even now, as if the damage he'd already inflicted was somehow not enough. "You filthy hanyou!"
"H-his face!" Shippou stammered, clinging fiercely to Kagome.
"He's changing into his true form!" Kagome cried.
Unlike his brother, Sesshoumaru was a full dog-youkai. Was he now going to take on the form of a dog? Sango wasn't sure what to expect, but she could certainly feel the change in the air as anger finally got the better of him. His power had been clearly and carefully restrained until now. It seemed he had finally reached the limit of that restraint, and was preparing to unleash his full fury upon his brother.
Miroku had made it clear that he thought it best not to intervene, but Sango readied herself to race for the hiraikotsu anyway. If Sesshoumaru took on his truest, most powerful form, she would not stand idly by and let him obliterate Inuyasha and the others.
The monk's hand found its way onto her arm again, a physical reminder that he would prefer she stay out of harm's way. The imposition annoyed her. Did he really expect her to allow Inuyasha to be killed? She was the only one in the group, except maybe for Toutousai, that had any chance of actually saving him. All of her training demanded that they fight together, not separately like this. Together they would be stronger. Strong enough even to challenge Sesshoumaru.
The point became moot a moment later. Inuyasha climbed to his feet and slashed toward Sesshoumaru, unleashing the full power of the wind scar technique.
The full force of the attack hit Sesshoumaru dead-on. The rest of them would have been caught up in it, too, except Toutousai urged them into the relative shelter provided by his ox-youkai just before it could hit. Wedged between Kagome and Miroku, Sango could only watch as the blast whipped past overhead.
If she had not just seen it for herself, Sango would not have believed Inuyasha was capable of releasing so much power in a single swing of his sword. He must have discovered how to read the wind scar, however improbable that seemed.
When the dust settled, there was no sign of Sesshoumaru. Only Inuyasha remained, breathing hard and bleeding.
"The match is decided," Toutousai said into the sudden quiet. And, just like that, it was over.