Yakumo was the heir of the Kurama clan. A savant in Genjutsu she was the pride of her clan. When her parents were killed in a fire, she was turned over to Yuuhi Kurenai to watch over. Sandaime felt Yakumo's talents were wild and could bring about disaster for Konoha. Kurenai later felt she could not properly train the young woman, so her powers were sealed away and she was sent to a mountain retreat for her own protection.
Raiga is a member of the Seven Swordsmen of the Mist along with Zabuza and Kisame. He appears only during a filler arc. He uses pikes as lightning rods (lightning is an energy source for him) and can put them together to make an even more powerful 2 bladed weapon. He travels along with a small disabled child named Ranmaru, whom is the only person he cares for.
A friend of Sagi and Toki. He is devoted to the siblings, willing to ask Konoha for help dealing with the ghost despite Toki (as Sagi)'s refusal of help. He uncovers Mousou's deception, and while he is nearly killed in the process, reports the finding to Toki and Naruto. He is almost killed by one of Oki's attacks, but survives. (From Naruto.Wikia)
Nagare and his partner Hokushin are wandering ninja. Nagare travels the world gathering jutsu and creating his own variations. The two men also act as mercenaries, working for whomever pays for their services.
Nan was a villager in a small village in the demilitarized zone of the Rice Field Country. The village had a small gold mine which became a target of bandits due to no government presiding over the area. Bandits led by Shiin attacked the village and killed a third of its citizens. Nan and her brother Ran survived. She looked after Fuki when the young girl’s parents died in the attack.