In reality, with Yamamoto's strength, it was naturally impossible for him to be sealed by Muramasa and his group. The reason he was sealed was that he had sealed himself.
Earlier, when Muramasa led Katen Kyokotsu and the others to the 1st Division to attack him, intending to obtain the location of Koga's sealing and the method to break the seal by invading Yamamoto's Inner World.
However, the moment Muramasa appeared, before he could even act, Yamamoto recognized him as Koga's Zanpakuto.
Knowing Muramasa's abilities, Yamamoto immediately sealed himself, preventing Muramasa from learning where Koga was sealed and how to break the seal.
With Muramasa's strength, let alone sealing Yamamoto, he couldn't even break the seal Yamamoto had placed on himself.
Even with the help of powerful Zanpakuto like Katen Kyokotsu, Sogyo no Kotowari, and Minazuki, Muramasa couldn't break Yamamoto's seal.
In this situation, Muramasa naturally thought of Toshiro. If there was anyone in the Soul Society who could break Yamamoto's seal, it would undoubtedly be Toshiro.
In terms of personal strength, Toshiro was not inferior to Yamamoto. In terms of Zanpakuto, one was the Strongest Fire-type, the other the Strongest Ice-type. Neither was weaker than the other.
No matter how you looked at it, only Toshiro was most likely to break Yamamoto's seal.
So Muramasa naturally pinned his hopes of breaking the seal on Toshiro.
But as a Shinigami, it is impossible for Toshiro to help Muramasa. That's why Muramasa wanted to control Toshiro's Hyorinmaru through his own ability.
After a Zanpakuto separates from its Shinigami and becomes an independent entity, its strength in the short term is completely not inferior to its original master's strength, and may even be stronger.
Because when a Zanpakuto is with its master, the master may not be able to bring out its full power. A Zanpakuto can naturally more perfectly exert its own power.
So as long as those materialized Zanpakuto haven't yet depleted their Reiatsu, their strength is actually a bit stronger than their original master's.
Therefore, if he could control Hyorinmaru, even without Toshiro, Muramasa could also break Yamamoto's seal.
However, contrary to Muramasa's expectations, although Hyorinmaru had indeed betrayed Toshiro, she showed no intention of listening to him.
"What should we do, Muramasa? I heard Hyorinmaru refused to become our companion. Without her power, relying solely on us, we cannot break Yamamoto's seal." Kyokotsu frowned slightly, her beautiful brow creasing as she asked Muramasa.
"There's no choice. We have to find Hyorinmaru and try to persuade her to cooperate with us." Muramasa said helplessly.
"Katen Kyokotsu, Sogyo no Kotowari, Minazuki, I'm sorry to trouble you to come with me to find Hyorinmaru. In case Hyorinmaru refuses to cooperate and even tries to attack me, having you there will ensure our safety." Muramasa requested earnestly of Katen Kyokotsu and the others.
"Don't say that, Muramasa. You are the one who liberated us from the Shinigami. We are all very grateful to you and will naturally do our best to help you. But if we all go with you, what about Yamamoto here?" Kyokotsu asked.
"Don't worry. Yamamoto, after sealing himself, has completely isolated himself from the outside world. As long as the seal isn't broken, he won't wake up. No matter what happens outside, he won't notice. So it doesn't matter whether someone is here to watch him or not." Muramasa explained.
"Of course, to be on the safe side, I'll have others temporarily guard this place." Muramasa added.
"Mm, that's fine." Kyokotsu nodded.
"Great, great! Let's all go find Hyorinmaru together. We haven't met her yet. We're really looking forward to it!" The two children that Sogyo no Kotowari had transformed into hopped and skipped, speaking in unison.
"..."
Minazuki, hidden in a white cloak with his face completely obscured, did not speak, but everyone knew he had no objection.
Seeing that none of them objected, Muramasa said, "In that case, let's go now."
Inside a certain rocky area within the Seireitei.
Hyorinmaru and Sode no Shirayuki wandered aimlessly, stopping and going, until they arrived here.
"Hyorinmaru-sama, where exactly are we going?" Sode no Shirayuki asked.
Hyorinmaru, like a child playing, jumped from one stone pillar to another.
"Mm... no fixed destination. The Soul Society is so big. Now that I can finally move freely, how could I not take a good walk and have some fun?" Hyorinmaru said casually.
Hyorinmaru kept jumping from one stone pillar to another, and before long, she seemed to tire of it.
"Alright, Sode no Shirayuki, let's go somewhere else." Hyorinmaru said, looking bored.
"Then which direction should we head next?" Sode no Shirayuki asked respectfully.
"Mm... let's go get some food. Although I don't feel hungry, I've never actually tasted the food that Shinigami and humans often eat. Toshiro often eats sweet natto. It seems to be quite tasty. Let's go try some, shall we?" Hyorinmaru suggested.
Sode no Shirayuki was stunned for a moment, not because of the suggestion to get food, but because Hyorinmaru... smiled.
Perhaps even Hyorinmaru herself didn't notice, but when mentioning Toshiro and sweet natto, a faint smile unconsciously appeared on her usually cool expression.
Seeing Hyorinmaru's smile, Sode no Shirayuki couldn't help but think, 'Perhaps Hyorinmaru-sama is the most beautiful Zanpakuto?'
Hyorinmaru didn't notice what Sode no Shirayuki was thinking and truly prepared to find some food to eat.
"Hmm?"
Hyorinmaru suddenly frowned and stopped in her tracks.
"Hyorinmaru-sama, what's wrong..."
Whoosh! Whoosh! Whoosh!
Before Sode no Shirayuki could finish, several figures suddenly appeared before them. It was Muramasa, Katen Kyokotsu, and the others.
"Eh? Eh? Are you Hyorinmaru? You're such a pretty onee-san. Mm, prettier than Katen Kyokotsu!!"
"Hyorinmaru, Hyorinmaru, let's play together!"
Sogyo no Kotowari buzzed around Hyorinmaru, chattering incessantly.
Hyorinmaru paid them no mind, but Katen Kyokotsu beside her glared fiercely at them.
"Why are you here, Muramasa?" Hyorinmaru looked coldly at the leader, Muramasa.
Muramasa stepped forward and said with heartfelt sincerity: "Hyorinmaru, we need your help."
"I think you know that I am the one who liberated you from Hitsugaya Toshiro. Of course, I'm not saying this to demand gratitude. It's just that besides us, there are countless other brothers and sisters who are exploited and enslaved by Shinigami."
"To overthrow the rule of the Shinigami and liberate all Zanpakuto oppressed by them, we need even greater power. And your power is indispensable."
"So, come, Hyorinmaru. Once again, I sincerely beg you, become our companion! Devote your power to the great cause of liberating all Zanpakuto!!"
Muramasa extended his hand to Hyorinmaru with a sincere expression.
In response to his invitation, Hyorinmaru coldly uttered a single word: "Get lost!"