After witnessing the death of his friend Nanami and Nobara,everything changed, making him see the world in a more different way, being more cold and distant, he hates Mahito for taking the life's of many and transforming humans into curses, and mostly for killing Nobara and Nanami. Yuji is a bit broken after All of that, he has a bit of depression and self harming tendencies because he thinks all of this is his fault