With Bleach: Thousand-Year Blood War currently on an amazing run, a lot of focus has been on the two-warring sides - the Shinigami and the Quincy, and their respective heads - Yamamoto Genryusai Shigekuni and Yhwach.
The latest episode from the anime was meant to feature their long-awaited rematch after 1000 years. However, near the episode's end, Yamamoto found out that he was fighting a clone of Yhwach all along.
With Yamamoto having unveiled all of his Bankai techniques, he was weakened from the fight and couldn't defend himself well, and thus he met his tragic end. But who was the one responsible for killing him, Yhwach or the Sternritter who cloned him, Royd Lloyd?
Disclaimer: This article contains spoilers from the Bleach manga.
Bleach: Who killed the Gotei 13 Captain-Commander Yamamoto Genryusai?
Yhwach killed Yamamoto Genryusai Shigekuni. While he did ask Sternritter Y 'The Yourself' Royd Lloyd to impersonate him and stay with the Sternritter Grandmaster Jugram Haschwalth, he never asked him to fight Yamamoto.
Yhwach knew he was the only person capable of handling Yamamoto's Bankai: Zanka no Tachi. He had, in fact, asked Royd Lloyd not to fight the Captain-Commander until he had arrived.
While Royd Lloyd was fighting Yamamoto, the real Yhwach had gone to meet the former captain of the fifth Division in the Gotei 13, Sosuke Aizen, to ask him to join the Wandenreich army. However, his proposal got rejected, after which he arrived on the battlefield, where Yamamoto had already defeated Royd Lloyd.
After seeing his fallen subordinate, Yhwach complimented him for having withstood for so long in his fight against Yamamoto. Royd Lloyd's prolonged fight allowed him to infiltrate the prison and meet Aizen. Now that Yamamoto had already exhausted himself, it was set to be an easy victory for Yhwach. However, before turning his attention to Yamamoto, Yhwach killed Royd Lloyd, who was taking his final breaths.
Just after Yhwach revealed to Yamamoto what he was doing under the Division 1 Barracks, Yamamoto activated his Bankai to fight him.
However, this was a grave misjudgment by Yamamoto, as Yhwach instantly stole his Bankai using his Wandenreich Medallion. He even revealed to Yamamoto how his analogy of stealing Bankai was incorrect. Yhwach said that a Quincy does not need to know their opponent's Bankai but should only be strong enough to control it, which is why Royd Lloyd did not try to steal it.
Yhwach then manifested a Sankt Bogen in the sky above him, which shot an arrow before him. The arrow turned itself into a Reishi broadsword, which Yhwach wielded to bifurcate Yamamoto diagonally from his left shoulder to his right waist.
However, Yamamoto still hadn't passed away and tried to grab Yhwach from running away, i.e., from leaving the Soul Society. Seeing the Captain-Commander's pitiful position, Yhwach started rambling about the First Generation Gotei 13, who were ruthless murderers, and how subsequently, the Gotei 13 shinigami who came after them were the weaker versions of them.
Insulting Yamamoto's hard work up to that point, Yhwach finally killed him, using one of his Quincy Reiatsu techniques.