He is another Dragon Knight who accompanied Atori and Tobi in leaving La'cryma. After removing his pipeline, he remarked that if he would disappear in a peaceful timespace then he would be happy. Fukurou and Karasu travelled to Haruka's timespace to pursue them, and when Atori ordered Isuka to destroy Haruka, Karasu was forced to kill him. Isuka's last words were that he could now be at peace. Isuka's spin weapon consists of him charging energy into his fists and unleashing a blast of energy shaped like a fist towards his target. Isuka is Japanese for crossbill.

(Source: Wikipedia)