|Home Country||Land of Fire|
|Nature Type||Yin Release|
Yoru was a living person at once, during the start of the establishment of villages, he was very skilled in Yin Release and Yang Release. He didn't belong to a clan and didn't really align with any villages, he was basically a loaner at that time. But then he was made an offer with a group of ninja that were coming to power and wanted to establish their own village and take over a land. To do that they had to take out a clan that was in the land, and that clan was the Uzumaki Clan. For Yoru, this was a great opportunity, one was he hatted the Uzumaki Clan for killing his parents and other village members during the Warning States Village. Two, was that he was tired of being alone, he could now establish his dominance with a group of ninja, and possibly become a leader or something.
Yoru wasn't an evil nor violent person at times, but when they were planing out the takeover of Uzushiogakure, its like another personality started to form inside him. He came up with plans of slaughter and violence that included killing children and women. It wasn't before long, that Yoru became the leader and commander of the attack, he had it all set and ready to go, his military had good moral status and went with the plan. In his plans it was like he knew everything that was going to happen, he planned for traps, back up plans, back up plans for the back up plans, the attack process, trapping process, and etc. But one thing he didn't anticipate was the truce and alignment with the Uzumaki Clan with Konoha and the Senju Clan. They had no idea about the Senju, and unfortunately for them, the day of the attack is when the Senju Clan and part of Konoha would go there for a festival for their alliance. In that festival would be the First Hokage, Hashirama Senju, Tobirama Senju; even the Uchiha and other clans, including Madara, Yoru and his group were completely ignorant about this.
On the day of the attack, Yoru and his men were about 1000 strong, and the Uzumaki were abotu 1500 strong, but with the added addition of Konoha and some of the strongest ninja of all time, the Uzumaki's man power was more like 10,000. Upon not even being 2 miles away from the Uzumaki clan and their village, Tobirama, had already sensed them coming. By the time they got to the suspected traps, and were ready for them. But, luckily for Yoru's group, they had a sensory ninja and he could sense the interception of their forces. Yuro used 100 men as pawns, while he split the other 900 into two groups to go around the little blockade and flank from each side. Tobirama was the interceptor of the 100 pawns and took them out within less than 10 minutes. The groups Yoru split up then start to attack from the side and meet massive resistance. The side that Yoru wasn't on faced mostly Uchiha and Sarutobi while the side Yoru was on faced Uzumaki and Senju. Not only that, but Tobirama's interception group started to join in.
It was disastrous for the pawns, and the people that were facing the Uchiha and Sarutobi, but Yoru's group managed to barely push the Senju and Uzumaki back. Yoru and his group moved up, only to meet Madara and Hashirama, being the cocky people they were Yoru's group charged not knowing who the two shinobi were until they fought them. In under 5 minutes, Yoru's group except him was wiped out, and Yoru was at the brink of death. He knew exactly who the two were and when Madara was about to kill him, the Uzumaki's leader came and told Madara that he would use Yoru for an experiment. Madara stopped and the Uzumaki's leader went to work. The technique he was testing would seal a person's body up, then as years pass that person sealed would still be alive until he dies, but during this period of time until death. The person's spiritual energy and chakra gets separated from the person as time goes on. Then when the person dies, the seal still won't be able to be undone, but to undo it, anyone's chakra, just a little touch with chakra on the seal undoes the seal. Then when the seal is undone, the person's spiritual energy and chakra can go into someone or split up their chakra and spiritual energy to different people. The Uzumaki knew that the person who was sealed would still have its consciousness on events in their life, so they made the technique for older people, so when they die their spiritual energy can go into a person for knowledge and chakra can go into someone to gain another nature.
The Uzumaki told Yoru this and he ran and escaped though he didn't get far. He got to the boarders of the leaf village when he was caught, so they did the technique there, to mark the location they had Hashirama build a tree over the seal, and they would come back to it later; but the Uzumaki didn't live long enough to see that. As time passed, Yoru died and his spiritual energy and chakra separated, all he needed was for someone to place chakra on the seal, but he didn't anticipate a over 100 year long wait when 3 boys did it.
At first, before the plan to take out Uzushiogakure and the Uzumaki clan Yoru was a nice person, a loner, but he got tired of being one. When he joined that group, he became violent and had more blood-lush intent. Some of the things he did and planned were evil, nothing good about it. And through the years of being sealed, be just became more and more mad about things.