I have been trying to find this manga or maybe manwha. The setup is 2 brothers separated at birth because of some time of skull artifact or something chose one of them to be evil or something. The evil brother plunges into his sibling, so they banish that kid from thing kingdom letting the evil one to become king. The kid who was banished ended being a mercenary and is somewhat immortal because of the skull artifact. Does anyone know the name of this series? Thanks in advance.