Shayan and Shanin are descendant of the hidden Mist Kyoryoku Clan. They were sent to Konoha to be Shinobis and grow up there together with they're Sensei Erisoo. They grew up with a dream: Piece in the Shinobi world! That's why Shayan (The younger brother) wanted to be Hokage... If you want to know more then read the book!