Declaration of War

The Senkaimon opened at the doors of the Seijin Temple. Out of it, walked Koga, Renge, Kento, Tenyo, Ken'ichi, and Seireitou. Koga did the honors of opening the giant doors for the group, "Don't worry, Haruko-chan. We'll be back for you soon..." he thought as he entered the temple complex.

Within the complex, they were greeted by Masters Kamui and Sorata Nekoi, as well as Grandmaster Junsui Kirei. "Welcome everyone." stated Kamui, as Seireitou walked up toward him. "Kamui, we took out one of the Five. I figure that should lessen the forces that the Arrancar possess. Also... we learned that the Arrancar are being led by a man known as Takashi Sora." he conveyed.

Junsui narrowed his eyes, "Sora, eh? It's been a long time since I've heard that name. I see that you lot are out one member." he noticed. "What happened-?" however, before he could finish his sentence, he noticed Koga with hollowified eyes. "Koga! What happened to you?!" the old man roared, showing a rare moment of shock. Koga looked at the floor, "I'm not entirely sure of the details, Master. All I know is that it has something to do with Sora and the Hōgyoku." he explained.

Seireitou sighed softly, "It appears that Sora is planning something strange... I am almost worried this will involve similar events as the era with Aizen and the Kurosaki brat." he suggested.

Junsui stroked his beard, "Kurosaki...Ichigo.." he muttered. "A brat indeed, only this time we won't let things get out of hand. We need to prepare for combat against the higher ups. Any suggestions?"

Looking over to Koga, Seireitou smiled softly. "I suggest having the Seijin Order set up perimeters around the Seijin Temple and surrounding Rukongai in case of attack. Now, regarding Koga. I believe I am the best person to continue his training, if thats alright with you, Junsu-jii."

Junsui looked to Koga and then over to Seireitou, "Yes. Yes. I would agree to that. I relinquish his training to you. Master Renge, come with me. We shall begin setting up the defenses of Soul Society." he said. Renge nodded and left the area with Junsui. Koga returned Seireitou's smile and then spoke, "Well. What do we do now?"

Seireitou looked over to the sky above, smirking. "So, almighty Koga. Open us a path to the Dangai." he ordered comically. However, the next instant, his look was of dead seriousness. "Alright... Whatever power this inner being has granted Koga with, its time to put it to the test.."

Koga picked up on this, "Alright, here we go." he said, as a seal appeared on his hand and in the air in front of him. "Kaiganseki!" he declared, opening up a hole in the dimensions that lead to the Dangai. Koga stepped inside and into the Precipice World. "Here comes your first test on the path that has been set before you." said the spirit of Tenbatsu within his soul. "Be alert, be ready. You will learn to control your new powers during this training. The other you might show up as well, so be ready at all times."

Inside the Dangai!
As the duo entered the darkness and dampness that is the Dangai, an unexpected visitor had been ramming through the corridors of the Dangai Precipice World. "Stand back." stated Seireitou, as he held out his hand, forming a dense sphere that appeared like a mini-sun of sorts. "I recently learned to access my Shikai abilities without having to draw my weapon. Though, I haven't mastered this yet..." he stated, he launched the mini-sun, causing the Kōtotsu to completely explode into millions upon millions of flesh remains, scattered along the Dangai.

Koga shielded himself from the blast wave, "Remarkable..." he whispered to himself. "Alright. I'm listening to you, Master. What do you have to teach me?"

Seireitou looked over to Koga. "Jinzen. A power practiced since the formation of Soul Society to communicate with one's sword. In order to move on to Stage Two of our training regimen, you will need to communicate with Tenbatsu. However..." he began, looking down by tilting his head off to the side slightly. "..This Tenbatsu will go wild."

Koga nodded and got into position, focusing deeply on his sword. He receded into his inner world where he found Tenbatsu standing directly across from him. "So you've come." the spirit said, summoning it's Shikai weapon form. "Tenbatsu, I have come here to master whatever you have left for me to learn." Koga replied. Tenbatsu cocked one eyebrow, "Really? You mean my Bankai? There is so much more to my power than just a Bankai, but I guess you wouldn't know that yet." he replied. Koga narrowed his eyes, "What's up with this? Tenbatsu just spoke to me not even ten minutes ago and he wasn't like this." But as he thought this, the form of Dark Koga appeared next to Tenbatsu, "Yo, Landlord!" he called out. "Wondering why Tenbatsu got so mean? It's because there is a part of you that is still clinging to me!" the dark side said, drawing it's sword. "That's...!" Koga exclaimed. Dark Koga let out a cold laugh, "That's right, this is Ryūjin Koji, your former Zanpakutō! It's mine now. It's the source of my power." he explained. Tenbatsu tossed Koga the sword in his hand, "Here." he shouted. Koga caught the sword by the hilt, but only barely, "Great. Now what?" he asked.

Dark Koga cocked his own eyebrow and laughed again, "So you just fight with any sword handed to you now, eh? This is a battle to keep your Seiatsu powers boy!" the inner being screamed. Koga's eyes widened, "Sei-seiatsu?! I'm a Human!" he shouted back. This time Dark Koga roared with laughter, "Not anymore kiddo. You're a Seiatsu. You've been one ever since I let go of my control over you back in the Menos Forest!" Koga gritted his teeth, "Stop playing games! Seiatsu or not, I'll control these powers." he said firmly. "Oh?" asked Dark Koga, "Are you now? You don't even know what you are and you think you can control it?! A Seiatsu is a being that, when fused with the Hōgyoku's power, stands at the crossroads of all spiritual races. You're not a Shinigami, a Hollow, an Arrancar, a Xiāochú, or even a Shinkūmyō! By definition, you're all of them squished into one body! That's the magnificence of the Hōgyoku's Desire Materialization." the Dark Side explained. Tenbatsu spoke up now, "Dark Koga, over there, is the manifestation of the Hōgyoku that gave it's very essence to you when Takashi Sora stupidly tried to transform you. If you fail this test, your powers won't be accessible to you and you'll fail horribly against the Arrancar." he said.

Koga closed his eyes for a moment, "What do I have to do?" he asked. Tenbatsu smirked, "Simple. You must drain all of his reiatsu from his body and take it for your own. This isn't like a normal battle that Vizard make in their inner world, where fighting alone is enough to gain control. Dark Koga is the Hōgyoku's power and energy, so in order for that power to be truly yours, you must drain it from him for yourself. Once you do that, it'll be yours forever." the spirit explained. Koga clenched his blade tight, "Alright, lets do this darker me." he said to Dark Koga. Dark Koga nodded and began gathering a massive Cero blast at his chest. He then fired it at Koga, in a much more massive version than Koga's own Cero. Koga began to shield himself, however, Tenbatsu appeared in between them and swatted the Cero away. "Why do you cower Koga? Do you think mere size matters? You have my sword form in your hands! Fight with me!" he shouted. "This will be the last time I will step in for you." Koga nodded, "Thanks Tenbatsu." he replied as energy began to gather on his blade. "Zaiten Tenshō!" he roared, firing the blast from his Shikai-level blade, right for the seemingly furious Dark Koga, who caught it with his bare hands and smashed it. The shockwave that resulted sent Koga flying backwards.

Koga flipped around and launched himself towards Dark Koga, who did the same and the two engaged in fast hand-to-hand combat. "He's much faster than me...!" Koga realized as he was again knocked away. "You're gonna lose your powers at this rate!" the Dark Side taunted. "Not likely!" Koga yelled, smashing his blade against Dark Koga's. With his foot, he kicked Dark Koga into a cliff within the inner world and then followed up by charging a black Cero of his own in his hand. "Cero Oscuras!" he declared, firing the black and purple Cero wave. The blast hit home, causing tremendous damage to the surrounding area. However, Dark Koga survived, using Senkō to appear right in front of Koga and grab his head. "I'm the one that killed your mother!" he forced into Koga's mind, causing the latter to drop his blade and go limp. "When you were little, you couldn't control your darker half. One day, you turned me on Tenyo after becoming enraged at a kid who was bullying him. When your mother tried to stop you, I made you kill her!" Dark Koga explained, revealing every gruesome detail. Suddenly, Koga summoned his sword back to him. "Then I'll be doing my mom a favor, by avenging her here!" he roared. "Bankai!"

An explosion ripped through the inner world and when it cleared the blade of his sword had lengthened and the hilt of his sword shortened, making his Zanpakutō into the shape of a nodaichi. The hilt was now yellow in color and the guard was in the shape of the kanji Ten(天, Heaven) as well as being black in color. His outfit was now similar to the one he always wears, only now it is a white cloak that is split in four sections near his waist. There was a cross in the middle of the cloak, similar to the appearance of a Demi-Seiatsu when they had the Hōgyoku embedded in them. He also wore form fitting white pants that double as boots, as they cover everything from his waist down. "I'll end this here! Zaiten Tenshō Niōda: Han no Zennōsha!" he roared. Dark Koga was hit with strike upon strike, forcing him to the ground again. Dark Koga's reiatsu began to flow from him into Koga himself, causing the dark side to panic. Dark Koga launched himself towards Koga in a final desperate act to kill his master, but Koga was ready. "Vanish, dark one!" he declared, "Zaiten Tenshō Saishūōda: Shinrabanshō Sanzen!" A brilliant golden wave over came the dark side of Koga's soul as the last of it's reiatsu united with Koga, and it then vanished. When the smoke cleared, the inner world began to fade. "Good job young one." Tenbatsu said as he returned to his spot, "You've earned that power...my power." he told Koga as Koga returned back to the Dangai and opened his eyes.

Seireitou has watched his body the entire time, and smiled softly as Koga's eyes had slowly opened. "Well well, Koga. You survived." he commented.

Koga looked down at his sword and gripped it tightly by the hilt, "It seems so." he replied, still in a daze. "I don't sense Dark Koga anymore. I wonder what happened." he thought. He then stood to his feet and sheathed his blade. "Looks like I've got a hold on my powers now. They aren't spiking or fluctuating so much, and this spiritual energy is becoming more comfortable to me." he explained.

Seireitou nodded, as he took off his brown robe, revealing his tannish tunic-like uniform. He then slowly brandished his blade, holding out to his side. "Now here comes Stage two. If you can land three direct slashes connecting from my shoulder length to waist. However... this must be done before... I kick your ass." he challeneged.

Stage Two: Seireitou Kawahiru vs Koga Tensei
thumb|262px|right|Seireitou vs Koga begins Koga brandished his own blade, settling it into an attack stance in front of himself. "Now it's time to use what you learned today in combination with what you learned against Xerxes. Only with that can you defeat Seireitou." Tenbatsu explained. Koga nodded his response, "Very well. I shall not let him take me down." The spirit of Tenbatsu nodded, "I'm temporarily taking away your Shikai and Bankai." it informed him. "What?!" he shouted, "Why?!" The spirit almost giggled, "To teach you of your other release. Your Tenkai. You can release when ready." Koga's eyes widened, "Tenkai?! Seriously? And why should I release so early on?" he told the spirit mentally. "Simple." it replied, "Because the timing of a release is only about pride. Use it now, when you are at your greatest advantage and gain the upper hand. You have one advantage; Seireitou doesn't know anything about Seiatsu except what you show him. He's curious. Now fill that curiosity." Koga nodded and then held his sword out in front of him, "Dominate the Heavens, Tenbatsu Niokeru-Kōmorihagai!" he shouted, releasing black and purple energy into the sky, forming a pillar. Within seconds the energy crashed to the ground in wave form, revealing Koga with a more form fitting version of his white attire and black bat wings. "Ready, Sei-san..." he said in a low voice.

Seireitou was surprised somewhat at this new form, "Hm.. so that's what I was sensing all this time. For a moment there, I was hoping that my senses were tricking me... Tch, looks like this won't be easy." He threw his sword up into the air, as he smirked. The very instant the blade stabbed through the ground as it landed, Seireitou immediately appeared to Koga's left, attempting a knee-thrust to the latter's stomach.

Koga blocked with his left wing and flung Seireitou away. "Don't get cocky now." he told himself, "Think. Seireitou is a tough opponent. Just transforming will never defeat him. I have to do this the hard way. I have to fight with everything I've got and then some." Without warning and without a pose, Koga fired off his Cero Oscuras from his chest, traveling towards Seireitou at tremendous speeds.