Tsukiko is the younger sister of Soo-Woon and childhood friend of Princess Yona and Hak. Tsukiko and Yona are like sister, always together just like Soo-Woon and Hak. Tsukiko visit the Kouka Kingdom earlier to celebrate Yona's 16th birthday with Soo-Woon. She was with Yona when they had a bad feeling and went to the King's room. " S-S-Soo-Woon," Yona gasped as Tsukiko walked behind frozen. She is shocked seeing King Il fallen as her older brother Soo-Woon stood there with a bloody sword. " Onii-san....," Soo-Woon look up shock to see his beloved sister witnessing him killed the king. He only wanted Yona to have witness it but couldn't believe that his sister was also there. With the help of Hak, Tsukiko and Yona fleed the kingdom from the wrath of Soo-Woon. Tsukiko's love for her brother has changed yet something tells her that she could still change him. " Tsukiko-san, your fate is to train their powers and to tame the four dragons when they are in conflict with one another. The four dragons will not only protect Princess Yona but you as well. You are the prophecies Dragon Tamer," Ik-Soo said looking at Tsukiko as her eyes widen in shock. Their journey has just begun and with the help of Hak and a beautiful boy name Yoon, Yona and Tsukiko will go find the four dragons to lend their powers to stop Soo-Woon.