Episode 54

The Backlash Wave: Tetsusaiga's Ultimate Technique is the fifty-fourth episode of the InuYasha anime.

Synopsis

 * 1) After his yōkai blood has taken over him again, Inuyasha begins ferociously attacking Ryūkotsusei and manages to slash him with his claws; Inuyasha could've defeated him this way, though if he had his Tessaiga would have not become any lighter.
 * 2) Inuyasha proves that he still has control over himself and picks up the Tessaiga; soon after he notices that not only is the Tessaiga lighter, but he can use the Kaze no Kizu at will.
 * 3) Ryūkotsusei prepares to finish off Inuyasha with another energy blast, but, unbeknownst to him, Inuyasha cuts through the blast and uses the Bakuryūha, slicing Ryūkotsusei to pieces.
 * 4) Tōtōsai reveals that the Bakuryūha takes the opponent's own yōki and fires it back at them, along with the Kaze no Kizu; Tōtōsai also notes that the user must have greater yōki than the opponent or the Bakuryūha will not work.

Summary
As Inuyasha lays, knocked out by Ryūkotsusei, Kagome and her friends, along with Tōtōsai, arrive and witness the scene. Inuyasha wakes up to the sound of Kagome's voice, but he has been separated from his sword and taken his full demon form. He then fights with his bare claws, to Tōtōsai's sorrow, because even if he wins, the Tessaiga won't become lighter for him. As Kagome is prepared to go with him to help him overcome his demon's blood's influence, he manages on his own to try to get the Tessaiga. Ryūkotsusei fires two fireball at him, the first one Inuyasha deals with by protecting himself with Tessaiga's sheath, the second one is diverted by Miroku's wind tunnel. Inuyasha then reaches the Tessaiga, which helps him regain his normal hanyō state.

Inuyasha forces himself to use the Tessaiga, which then becomes lighter. He strikes the dragon to the heart, and marvels at how the blade now seem to belong to his hand. But Ryūkotsusei isn't dead yet, barely scratched. Tōtōsai remarks that he was a handful even for Inuyasha's father, and won't die unless torn to pieces. Inuyasha uses the wind scar against him, which he can now wield at will, but even that isn't enough. Ryūkotsusei taunts him and prepares to send a monstrous ball of pure evil energy. Kagome and her friends go a little farther from the fight for their safety. The dragon launches the thing, and Inuyasha goes head on against it, cutting it hard with a "different wind scar". He just employed in battle the Backlash Wave for the first time. Ryūkotsusei's energy is sent back at him tenfold, in the shape of multiple twisters that rip his body apart.

As Kagome, Shippō and Miroku congratulate him on an impressive victory, Inuyasha shows off his perfected Wind Scar, to the point that Kagome has to use the sit command to calm him down from his bragging.