Jaku-chara Tomozaki-kun - Volume 1 Chapter 1 part3

The brash Li Chengfeng makes a living through trickery with his clueless but loyal servant, Xiaobao. One day, the love of his life is murdered, making him a suspect, and he meets a demon who suspects he is the reincarnation of a traitorous immortal.

He was confused, so he asked, “I have a car, a house, good-looks and money. What am I lacking in?”

Cassian Ven Dyke, the bastard son of a powerful ducal family, grew up in the slums of Veldora under the care of his father figure, sword master Russel. When Russel passed away, Cassian was left with only a silver necklace as his inheritance. After putting it on, Cassian was attacked by three psychotic thugs who tortured him in an attempt to steal the necklace. Refusing to give in, Cassian was ultimately stabbed through the heart with the very same necklace. Instead of dying, he mysteriously vanished as the necklace lodged itself in his heart. Just before disappearing, he heard an eerie message echo in his mind:[True mana detected. Origin: Human...][Human detected. Compatibility with system: Confirmed.]