Revenge
After learning to better use Shiro's power, Karasu decided it was time to leave. He stared at the ruins of his childhood home, remembering the good times as he prepared himself mentally to leave behind everything he knew. There was still an important decision for Karasu to make; to go after his uncle and help him in his fight against Madara, or to track down Danzo and get revenge for the horrors he had been put through. He didn't know which path to choose. On the one hand, his uncle could probably handle Madara with the help of the one that always chased after him. On the other, Danzo would be next to impossible to locate.
As he sat thinking on which course to choose, an idea occurred to him. He tapped into Shiro's power, focusing his thoughts on his uncle. His vision soared across the land, locking in on his uncle within a hidden facility within the Land of Fire. He did not recognize any of the people with Sasuke, but he didn't need to recognize them to know that Sasuke could handle the situation himself if things took a bad turn. Content that his uncle was as safe as could be and likely getting help on his own grim task, Karasu turned his thoughts to Danzo. His sight traveled far to the north, to a land covered in snow. He found Danzo on the road, traveling deeper into the cold land with two guards. Karasu could see movement within one of the men's bodies, finding the source to be a swarm of insects living inside him.
The visions he saw with Shiro's eyes helped clarify his dilemma. Sasuke was already well on his way to accomplishing his mission, leaving the hunt for Danzo as Karasu's more logical course of action. He locked Danzo's location into his mind, switching from Shiro's power to Koku's as his black flames took on the dragon's shape. He took to the air, propelling himself through the air by using his burning wings and jets of black fire as he steered towards Danzo. With the speed he could achieve with Koku's power, he was confident he would reach the Foundation leader within a day and a half at most.
He entered the snowy landscape he had viewed from afar as the sun began to set, painting the snow and ice with beautiful colors as Karasu stopped to regain some strength before going after Danzo. He admired the natural beauty, wishing his parents were there to enjoy the scene with him. A strange sound brought his attention back to his surroundings. He scanned the area, spotting a swarm of insects flying straight towards him. Karasu knew it was likely from one of the men with Danzo, sending a jet of black fire towards the swarm as it neared.
He was able to incinerate the swarm, but he suddenly became aware of another presence nearby. He felt someone trying to push their way into his mind, his head feeling like it was in a vice. He heard the dragons within him growl as they reacted to the foreign presence, throwing their minds at the would-be intruder. Karasu heard a man cry out in pain somewhere behind him. He activated Shiro's ocular power to keep an eye out for his prey, finding the two ROOT operatives on either side of him as they tried attacking him from both sides.
Karasu felt his right eye activate with the Kokuryutei Sharingan instead of Shiro's, though the other orb retained Shiro's power. He combined the two ocular abilities to capture both men within a genjutsu, acting on instinct as the dragons' minds seemed to overlap with his own. He didn't know it at the time, but Karasu had cast the Tsukuyomi on both men, the dragons using the opportunity to torment them with images of being devoured and slaughtered by them for what seemed to be several days. Both men collapsed in the snow simultaneously, babbling incoherently. Karasu checked them with Shiro's eye, finding their minds completely shattered by whatever the dragons had done to them.
A strong wind suddenly picked up, sending Karasu flying through the air to come crashing down into the snow and the stone beneath. He rose, spying Danzo not far away. Koku's black flames covered his right hand even as Shiro's white ones covered his left, his eyes blazing with murderous rage as he stared at the man responsible for so much pain.
"You must be Itachi's brat. I'm glad I was able to attend the Kage Summit before having to deal with you" Danzo said disdainfully.
"I must say that I'm a little disappointed though, I thought you'd be harder to knock around," he added as he appeared before Karasu, hand drawn back to strike.
Rather than dodge, Karasu let Danzo's strike reach him. The flimsy genjutsu broke as Danzo's attack connected, leaving the man open while he wove the hand signs he had been trying to hide. Karasu slammed his left palm into Danzo's stomach, instinctually using Shiro's white flames to completely seal Danzo's chakra. He stabbed his right hand, covered in Koku's deadly black fire, through Danzo's chest. Karasu noticed a strange flux in the chakra of Danzo's right arm as the man suddenly appeared whole standing a few feet away. He caught Danzo off guard by blasting his side with Koku's fire, destroying the man's robe. He stared in enraged shock at Danzo's now uncovered arm, the limb being covered by several Sharingan eyes.
"You would steal the Uchihas' eyes to create such an abomination?" Karasu asked, his voice trembling with rage.
Danzo's only response was a cocky smile, a smile that quickly vanished when pain erupted in his right shoulder. He looked down to find his arm missing, spotting the severed limb in Karasu's right hand. His hardened heart dropped down to his bowels as Karasu's black flames consumed the limb in an instant, leaving him with only the Sharingan implanted in his socket. Before he could remove the bandage that his his trump card, Karasu snatched the eye from his skull.
"You are not worthy to know the Sharingan's power," Karasu growled as he crushed the eye in his hand, burning away what remained with Koku's fire.
Danzo tried to take a step back, only to feel something against his back. He looked up to see a massive black dragon staring at him hungrily. He could feel his heart hammering in his chest as he turned and back away again, only to once more bump into something. He tried to dispel whatever genjutsu Karasu cast, not realizing that the dragons had actually projected themselves from Karasu. They wanted their own revenge against the man, for all the blood he had spilled from the people descended from the ones that first used their power. Koku and Shiro took their time ripping him limb from limb, using their fires to cauterize the wounds as they were inflicted to keep him alive throughout the whole gruesome process. Rather than finish the man off themselves, they gave Karasu that honor. He stepped forward, plunging his father's sword through Danzo's chest. The blade erupted in a swirl of black and white flames as Karasu channeled both dragons' power into it, the fires consuming all trace of the horrid man's existence. He let out a heavy sigh, closing his eyes as he turned his head toward the sky.
"This was not to avenge you, mother, but to seek my own revenge for what he put me through. I have something else in mind to honor your memory," he said solemnly, turning around and trudging back towards the Land of Fire, a new goal already formed in his mind.