The Simple Life of Killing Demons - Chapter 68Book 12:

Kieran was just an ordinary part-timer — a high school dropout who had also given up on boxing. With no parents and no real family, he survived by working his ass off every day. He was raised by a man he believed to be his father, but later discovered he wasn't — though the man passed away before the truth could fully sink in. What Kieran didn’t know was that he was actually the sole heir to a powerful business empire, the hidden son of a wealthy tycoon.

He was once a great Immortal, but his attempt to ascend the Nine Heavens ended in failure. Reincarnated on the Blue Star, as he opened his eyes, he found himself with an adorable daughter. And a stunningly beautiful wife?“Daddy, can you cast a spell for me?”“I could even pluck the stars from the sky for you.”

For the once dead Hua Yu Man, she has to do three things this lifetime: kill those who harmed her, kill the man who said he loved her, and protect a place called “home.”

She seems docile and gentle, with the air and temperament of a beautiful young lady. But in fact her heart is cold, overbearing, and black belly, with a mysterious identity that can drive the world crazy.

He is the Thirteenth Prince, but also the country’s disgrace; a cold and ruthless man who doesn’t put human lives in his eyes. But only towards a sometimes gentle, sometimes willful and sometimes disobedient woman, would this man be ceaselessly doting and spoiling.

- Description from Novelupdates

Ajax was an orphan who survives a massacre along with his friends but unfortunately gets separated from them.

Fortunately, after a turn of events, he successfully gains a system which helps him increase his cultivation, but doesn't know what it is called.

But he knows one thing for sure, this system is very powerful and helpful in taking his revenge.

“Whoever you are, I am gonna find you”, Ajax mumbled himself with a disgruntled expression.

In a world where Summoning of an elemental spirit is done through a dream when they are 15 years old, Ajax with the help of a system and his summoned spirits sets out on a journey to seek revenge against the mastermind behind the massacre.