The Young Heavenly Demon

The Supreme Ruler of Ten Thousand Demons has drawn his sword, so all demons shall bow their heads. Heavenly Demon Wi Jeong-cheon. The sword of the Heavenly Demon Divine Cult's pursuit squad pierced the chest of the man who was both a father and a teacher. At that moment, the boy resolved. Be it the Murim Alliance or the Sado Alliance, he would wield whatever sword he could grasp to cut down the Heavenly Demon Divine Cult. — Description from novelcodex.org