Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Book 4 - 4-8. Demon Lord Season

“You want to steal my genes then leave?” He grabbed her and tried to force her to hand over the child that was born three years ago.

Everyone in the City of Jing thinks that bestowment of marriage between Xian Junwang and the daughter of the Yi’an Marquis House is to insert a fresh flower into manure.

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.]