A World Between Humans and Demons: Half-Human and Half-Demon Abandoned by the World

I wielded a demon-suppressing halberd to protect the world, but in the end I found out that the innocent souls under my demon-suppressing halberd were all my own people. Since then, everyone has betrayed their relatives and separated. Even my sister who I grew up with killed me for my mission. What should I do as a young man caught in the collision of two worlds...