This article, Kouwa, is currently being worked on by the great person who shall most likely devour your body and soul cause he's hungry. So, give him some more time..
Kouwa Ōtsutsuki (講和大筒木, Ōtsutsuki Kouwa) is an Ōtsutsuki clansmen, and an invention of the feared 'Rabbit Goddess', Kaguya Ōtsutsuki. As the first and only individual to wield the Eishagan Kekkei Mōra and the progneitor to the Inyou Clan, as and such, he has access to their Clan's Hiden techniques, the two paths he has access too are much more powerful than other users, his chakra being one of the most potent to date. His mastery of the Hiden's earned him the name of Sage of Dual Paths (二重道賢者, Nijuumichikenja), and his mastery of his Kekkei Mōra earned him the moniker Kouwa of the Reflection (映射ザ講和, Eishazakouwa).
Despite being a creation of Kaguya, he was inwardly against his inventors' philosophy, and instead followed the ideology of his Chakra Relative, Hagaromo Ōtsutsuki, and learnt Ninshū. Since he had the chakra of both his Chakra Relatives residing within him, he was able to quickly learn how to utilize Ninshū effectively, eventually making secret techniques unique to him and a clan he would eventually form.
Kaguya was highly angered upon the realization of the fact that Kouwa had access to the Eishagan, and thereby had the potential to gain Sensory skills greater than her own, and Kouwa eventually did become much more powerful than his inventor, not only in sensory skills, but also in power. After his inventor had sealed Kouwa away, a recessive effect took place, and Kouwa was placed in a deep sleep, waking only after the disastrous Fourth Shinobi World War had ended.
After escaping the realm in which Kouwa had been sealed in, he was soon regarded as a Vigilante, acting against set laws. He did not immediately reveal his Ōtsutsuki bloodline, as he wanted nothing more chaotic to occur. During his time as a vigilante, Kouwa was known to go against direct orders from those of Kage-rank, and eliminate those who have 'failed his brother's ideology'. During his reign as a vigilante, he would go on to kill hundreds upon thousands of victims, all of whom had fallen within his criteria for extermination.
Soon, Kouwa dropped his vigilante act and revealed his true bloodline, revealing to all that he was indeed an Ōtsutsuki clansmen. This immediately caused turmoil to rise within the hearts of many, if not all the Hidden Villages. Kouwa attempted to solve the turmoil, which only caused coup's to occur within villages. To end the disruption to shinobi life, Kouwa hid himself away within a mountain, which only those with the fabled Yin-Yang Release would be able to access. Those with this exalted ability often searched Kouwa out, wanting to be tutored by him, and he has taken a few pupils.
Once aged twenty-three, he was soon engaged to his lover. Despite the considerable age gap of approximately seven years, the two ignored the fact, calling it 'unimportant', and many other slurs. After his marriage, Kouwa decided to settle down in Amegakure, the village that had initially taken him in. Kouwa has been offered to become the Amekage of Amegakure, but he has denied all requests, saying that the job would not be for him.
After the birth of his daughter, Kouwa's protective instincts highly increased, wanting to protect his child. Despite him being married to Shiena, Kouwa does have children from before meeting Shiena. Kouwa occasionally visits these children and that childs mother. Kouwa accomplishes this by using his dimensional technique, but on a much smaller scale.
Kaguya had struggled for ages, trying to create a new invention that would serve her with all of its heart. After utilizing a combination of both Hagaromo and Hamura's chakra, using Hagaromo's Yang half and Hamura's Yin half. Kaguya had invented a new potential servant, Kouwa. Kouwa struggled to be accepted by his Chakra Relatives, whom he considered actual siblings. Kaguya, on the other hand, accepted Kouwa for who he was, and the only clash between the two was that the two did not want to follow each others' philosophy.
By disrespecting the philosophy of his creator, he was often scolded and looked at shamefully. In an attempt to show his 'mother' that he wasn't a failure, he attempted to create an invention of his own, eventually creating Aouyoku, a blue-feathered crow. Upon showing his mother his creation, she was immediately angered, and tried to kill the crow that Kouwa had created, Kouwa responded by defending the crow, by unlocking the Eishagan (映射眼, Literally meaning: Reflection Eye). Kouwa transported the crow elsewhere, while his mother began to examine his Eishagan. Kaguya was confused at how his Byakugan had changed into this new Dōjutsu.
Kaguya quickly became infuriated at the fact that Kouwa's eyes would now allow for Kouwa to become a better sensor. So she did the only logical thing which came to her mind. She trapped Kouwa within a different dimension. This dimension was bitter and unforgiving, and the eight-year-old Kouwa was confused. Why had he been banished? He ignored his thoughts, as he summoned Aouyoku. The crow appeared, before shifting in a humanoid form. He bowed to Kouwa, before standing.
Aouyoku told Kouwa what had happened, and what his mother had done. Kouwa, still confused began to bombard Aouyoku with question. Aouyoku sighed, before transforming back into a crow and soaring off. As with any young child, curiosity got the best of Kouwa and he followed Aouyoku. Aouyoku had flown for miles, but the stamina-filled Kouwa barely noticed, his adrenaline keeping him running. Upon stopping, Kouwa was greeted to an army of strange creations. Aouyoku flew down, and landed on Kouwa's shoulders. The creatures all turned their heads in unison towards Kouwa. Upon making eye contact, the creatures attacked.