Karasu

He is Y in a future timespace Lacryma and is one of the protagonists of the anime. However though his mission was to find the Dragon Torque Haruka Karasu had an alternate reason as he removed his pipeline to remain in our timespace as Harukas protector. In his timespace he failed to save Haruka from death and thus swore to protect the Harukas of other timespaces from anyone or anything. His devotion is such that even torture and mortal injuries cannot stop him he even briefly goes mad when she is about to die triggering the memories of his Harukas death. As a result he brutally kills one of the other Dragon Knights and smashes open a dam screaming Go Hell calls you He even fights his oldest friend Isami/Fukur almost to the death rather than allow Haruka to be harmed. He is also irritated by the Y of our timespace seeing him as weak and indecisive although it seems that he despises Y for his own inability to save his Haruka. They are actually very similar with a psychic bond to Haruka a desperate need to keep her safe and a tendency towards angst and doubt. Karasu apparently still whittles. Like all Dragon Knights Karasus body has been radically altered on a quantum level when he is injured the inside of his body shows silver and he bleeds blue raizu particles. His spin weapon consists of several black whiplike threads that he can control. With them he is able to create shields grab distant objects and cut through most anything. He has also been seen using blasts of built up energy. The spirals on the arms of dragon knights can also become swords Karasu and Fukurou are seen using this weapon while fighting in episode 12 for a short while. Karasu is the Japanese word for crow. Due to the fifteen years that have passed and the strain of his life in Lacryma Karasu is not immediately identifiable as Y. While Y looks like an ordinary young boy Karasu has pallid skin silver hair that falls over his face and dresses in a huge black cloak. Despite these differences his eyes are the same as Ys and Haruka sees the resemblance between them. Wikipedia