Leech is the brother to Flaria Catex. He was considered a hero for a long time. Then, he met Titan. Titan taught him his ways and showed him the side of the world that he had never seen. In this process, Leech killed his wife and one of his children (The other managed to escape) thinking that they were of no use to him. He became an assassin who stood at Titan's side, a top commander at his round table. He followed him out of respect. He did not like taking orders, but he would take them out of his respect. He saw himself above others. He even killed his own sister and had to go on the run to escape Stain and Zexeo only because he had seen her as a waste of space. But, after a while, he began to decide that he was not at his full potential. He found out that Titan was holding a very risky experiment that would make someone able to transfer themselves into code and download information into their 'data base', making it possible to change features at any time. This was labeled as "Digitalization". Leech underwent the experiment, but at high costs. Due to the over flow of information without warning in such a short span of time, he went insane. He now only desired one thing, to kill those that were wasting air. And with his definition, no one was safe, not even his once respected mentor Titan. In the end, he was killed by his own niece as revenge for her mother's death. But some say some of his code is scattered throughout places he traveled.