Although most of the Espada had perished in their own battles, there was one that remained standing - Yammy Llargo. However, despite the number of people fighting him, they still struggled due to his size and power. He grew to a monstrous size, and his ponytail grew longer. Besides, his skull ridges became more pronounced, and extended to the back of his head. His white mask fragments fused to his face, becoming his lower jaw. His red markings extended from his face into two long flame tattoos. His body transforms drastically, with his torso remaining largely the same grew eight large elephant-like legs on each side of his lower body, extending back from his torso. Each leg was connected to his body by white carapace-covered joints, and led up to the base of a bony tail club. On each leg, he had three large toes which extended backwards from the front to the back of the leg. Large purplish-gray cylindrical tubes formed on his elbows, allowing him to use them as piston-like rams. He also gained five large, black cylindrical tubes on his back, and had six black rounded nodules along the length of his forearms. Aside from the change his appearance, his number changed from 10 to 0, showing everyone his actual rank among the Espada.
It was a tough battle for his enemies, and they were nowhere close to winning. Sado and Renji laid on the ground unconscious, and Uryu was being healed by Orihime at the top of the dome; the only one left to fight the monstrous Espada was Rukia, who was sent crashing to the ground. Just then, Ichigo joined the battle; and he, too, had a hard time fighting Yammy. Despite going using Getsuga Tensho while Hollowfication, the attack didn't do much damage to the Arrancar, who then proceeded to fire a Bala while berating the other Espada that perished. As Ichigo was hit by the Balas, he thought to himself that despite the fact that Yammy was the one with all of his comrades dead, Orihime still had a much more pained look on her face. Ichigo slashed at one of the Balas, destroying it, and told Yammy that he didn't expect him to know friendship, nor did he regret cutting down his enemies, but he still didn't like the fact that he talked trash about the people he had fought.
Ichigo then donned his Hollow mask again, but this time the mask immediately dissipated, catching him by surprise. "Wha-?" he exclaimed. Yammy took this opportunity to reach out and grabbed the stunned Shinigami. "Damn!"
The Arrancar laughed before saying, "I'm not sure what's going on, but it looks like you can't take out that troublesome mask anymore!"
'Damn it.' thought Ichigo. 'Why can't I take out my mask? Does it have something to do with that odd feeling?!'
"Well, no matter." continued Yammy. "You did well. Much better than that lying scum over there." A grin flickered across his face and he said, "Die, scum." At that moment, his grip on the Shinigami tightened, causing the latter to scream in agony.
"Hado #33: Sokatsui." Suddenly, blue flames were fired at Yammy, creating an impact that was strong enough to have dust clouds shrouding him. Right after that, the attacker cut off one of his legs.
"What?!" yelled Yammy, who soon fell to the ground and released the surprised Ichigo.
However, the Arrancar let him go from up high, making him let out a scream as he began to fall. "That hurt..." he muttered once he contacted the ground, with an impact that created dust clouds shrouding him. "What was that explosion? Jeez, I can't see anything below." But what, or rather, who stood before him caused his eyes to widen with surprise.
"Why are you attacking him before me?" growled Zaraki while giving Byakuya a side glare. "Stay out of this."
"What are you talking about?" questioned back the latter, who was mirroring his action. "I arrived here first. Know your place."
The 11th Captain humphed at this. "It's not my fault if I slice you up by mistake." he remarked.
"Um, I don't think now's the right time to be arguing about this." said Asa nervously with a sheepish smile.
"Byakuya!" called the surprised Ichigo. "Kenpachi! Asa-san!" Just then, he heard something from behind, prompting him to turn his head to see Yammy angrily get back up. "He got up already!"
"Step aside, Kurosaki Ichigo." ordered Byakuya, immediately grabbing his attention.
"Stop looking dumb." said Zaraki. "You get beaten up wherever you go. It's pathetic, so move out of the way, you piece of crap!" He raised his blade, which caused the said boy to watch nervously, and attempted to strike the latter, who quickly dodged the attack. Asa blinked owlishly at the scene, feeling both confused and amused.
"Wh-Wh-Wh-Wh-What are you doing, Kenpachi?!" yelled Ichigo after scooting away from him. "You swung at me for real! That's dangerous! Are you trying to kill me?!"
"That's right." replied the said Shinigami. "Wimps should die." With that, he began to charged towards Ichigo.
"Wait, Kenpachi!" he yelled desperately. "Now's not the time to be doing this." Suddenly, Yammy's fist headed straight for Zaraki and punched him into a distance. "Kenpachi!"
"That hurt." said the Arrancar, who managed to get up despite having to stand on his remaining legs. "That hurt, you piece of crap! I won't forgive you. I won't forgive you! How dare you cut my leg! I'll kill you, you damn bug!" Just when he was about to release his reiatsu, a huge rubble came flying towards him, to which he easily destroyed it with one punch.
"Oh, good." said Zaraki while placing his feet on a rubble. "So you can punch. That last one only gave me an itch. I thought you were some giant fly. If you're going to hit me, do it with all your might, maggot."
"You're an impudent little fly!" scowled Yammy, who then turned around to begin attacking the grinning Zaraki. "How's that?! Can't do anything, can you?! You're just a damn bug!
"Kenpachi!" called Ichigo worriedly, but Byakuya held his hand in front of him, preventing him from going forward.
"I told you to step aside, Kurosaki Ichigo." he repeated. When the said boy tried to argue, he continued, "There is nothing for you to do here. Hurry to the World of the Living."
"I'll go to the World of the Living!" he said. "But I've got to defeat him first! Besides, I can't leave so easily! Urahara-san has to open things up on the other side."
"My, my." came another familiar voice that caught him guard. "You sure make a fuss about Urahara."
Ichigo turned around with his eyes wide open, even more surprised to see who it was. "Kurotsuchi Mayuri." he muttered.
"A Substitute Shinigami dares address me without respect?" questioned the said Captain. "And he addresses that old man's granddaughter with respect instead? Humph! Well, I supposed it's better than being addressed on a first-name basis like you do to those two."
"How generous." said Byakuya sarcastically before his gaze landed on the huge item Nemu was pushing. "Is it because of that cart?"
"That's right." replied Kurotsuchi. "I've just obtained some rare treasures. I'm in a very good mood. Furthermore, I was able to analyse the structure of the Garganta at the place where I obtained these treasures."
At this, Ichigo got up with surprise. "Analysed... the Garganta?" he repeated with disbelief.
"That's right!" responded the Captain. "Furthermore, it has no flaws! It lasts nearly indefinitely! I can just imagine his look of frustration! There is no way I can't be in a good mood! I can easily overlook the chattering of a rude monkey! Make preparations, Nemu! We're going to send this Substitute Shinigami to the World of the Living!"
"Yes, sir." she responded before proceeding to do what she was being told.
"Wait!" called Ichigo. "I still-"
"Shut up." scolded Kurotsuchi, cutting him off. "You're a test subject, so don't talk. This is an experiment! You have no idea to refuse or decide anything." He then pointed a finger at him and added, "Listen. You are test subject number one!"
"Test subject?" repeated Ichigo.
"There's no need to worry." assured another voice, making him look up to the source. "I'll go with you."
"Unohana-san!" he called when she got down from the cliff.
"I never expected a volunteer." said Kurotsuchi. "You're out of your mind, Squad 4 Captain."
She merely gave him a closed-eye smile and said, "I trust you, Kurotsuchi-taichou. It's alright. You're experiment will be successful." She then opened her eyes to look at him and taunted, "After all, you've come all this way to Hueco Mundo and analysed a Garganta using data from an Arrancar scientist. If you fail, Urahara Kisuke will surely laugh at you."
"Think before you talk." he threatened. "Since I've analysed the Garganta, I can close it while you're passing through it!"
"That's impressive." she praised with a smile before turning to her Lieutenant. "Isane."
"Yes, ma'am!" responded the said woman while rushing towards her.
"You stay here and assist Kuchiki-taichou." she ordered.
"Understood." responded Isane.
Unohana then turned to Ichigo and said, "Now then, Kurosaki-san. Let's go."
"W-Wait, Unohana-san!" he said. "That Yammy is really strong! I should stay here so the three of us can fight him!"
"Don't get cocky," Kurosaki Ichigo." said Byakuya, causing the said boy to look at him. "A Captain of Gotei 13 doesn't need help from the likes of you."
"Byakuya..." he trailed off.
"What is your duty?" questioned the Captain. "Your duty is to protect the World of the Living." He turned to look at him over his shoulder and said, "Go. You're Karakura Town's Substitute Shinigami."
It took him a while, but when Ichigo thought about it, he gave in. "Yeah." he said. "You're right." He then walked towards the portal where Kurotsuchi prepared to open the Garganta, just in time for Rukia to run up to him. Upon hearing his name, he turned around to face her and declared, "I'm going."
Rukia then left to Isane, who was inside an orange barrier healing Renji and Sado. On the other hand, Asa was standing next to Byakuya with her gaze on Ichigo waiting for the Garganta to open up so he could leave with Unohana. A lot of thoughts wen through her mind, thinking about Ichigo having to encounter Aizen in the World of the Living, and if this were to happen, she had to tell him something crucial; one that would determine the faith of everyone's lives.
"Unohana-san, do you mind if I talk to Ichigo for a moment?" she asked the Captain.
"No, I don't." she assured. "Please, go ahead."
Asa smiled and gave her a bow. "Thank you." She then turned to the boy and called his name, getting his attention. "Can I have a word with you?"
"Now?" he asked, earning a nod. "O-Okay." He followed her to the side where they were away from the others. "So what do you wanna tell me?"
"I need to ask you something." she began seriously. "You encountered Aizen at the Sokyoku Hill once before, right?"
"Yeah." he replied. "What about it?"
"What did you think?" she questioned back.
Ichigo looked to the side to remember how the encounter went down. "There wasn't much to think about." he said. "He had monstrous strength. I was completely helpless. He didn't even use his Shikai. It was a one-sided battle."
Asa's brows furrowed at this. "He didn't use his Shikai?" she repeated.
"Yeah." he replied.
She let out a sigh of relief and said, "That's good." Ichigo wasn't expecting such a response and looked at her with confusion. "The fact that you had such a large difference in strength was your greatest fortune." She looked at him in the eyes, continuing, "I shall tell you now, Ichigo. At the moment, you are probably the only person in the World of the Living, Soul Society and Hueco Mundo who can fight Aizen."
The said boy's eyes widened, for he was becoming more surprised and confused by this. "What do you mean?" he asked.
"Before I tell you why, I must tell you about the powers of his Zanpakutou, Kyoka Suigetsu, and the requirements for activating it." she began, and that was more than enough to grab his attention. "I was his Lieutenant many years ago, so I knew almost everything about him, as well as the abilities of Kyoka Suigetsu; especially the Complete Hypnosis. It controls the five senses to the point where it can make the target misinterpret another person's form, shape, mass, feel, and smell to be an enemy's. All it takes is to show the release of Kyoka Suigetsu. After seeing it just once, the witness will completely succumb to the hypnosis; and every time it is released, they will still fall for the hypnosis."
"Anyone who sees it... even once?" repeated Ichigo with surprise.
"That's right." said Asa. "Me, the Captains of Gotei 13, the Visored, his subordinates, the Arrancars and the Espadas, as well as everyone who is possibly involved in the battle in the World of the Living has seen Aizen's Shikai. That means everyone, but you. You posses a reiatsu that rivals that of a Captain, and you have not seen Kyoka Suigetsu's Shikai form."
"So as long as I don't see Aizen's Shikai, I won't fall under his Complete Hypnosis?" he clarified.
"That's right." she confirmed. "Your advantage is very important in this battle. No. More accurately, if you lose that advantage, this battle is over. Ichigo, no matter what happens in this battle, from here on out, do not look at Aizen's Shikai. Ever."
He stared at her for a moment and nodded. "Got it." he said. "Thanks, Asa-san. I'm glad I heard that before I went into battle. Hearing that is more than enough. I'm the only one, right? Then it's decided. I'm going to defeat Aizen!"