MTL - Therapy Planet No. 13 - Chapter 85 motif

«Until death do us part.»That was our vow.And she kept it... by driving her sword through my chest.I was a hero. A symbol. The one chosen by the gods to free humanity.I fought for her. For us.But in the end, it wasn’t the demons who killed me.It was the woman I loved.Helena betrayed me.I fell with my heart shattered and my blood burning between my fingers.But death wasn’t the end.I woke up in another body, in another world...No, not exactly.I woke up inside the very story she wrote.And now, I am Daven von Riesenhart:the bastard son of a marquess, a noble outcast with a name no one respects, and a life I never asked for.I no longer believe in ideals, in gods, or in happy endings.I won’t fight for others.I won’t die for anyone.This time, I’ll live only for myself.And if surviving means deceiving, betraying, or destroying...so be it.Even if it makes me the villain of this story.

A genius talisman practitioner is reborn as a seven-year-old girl! However, her innocent appearance belies her vicious personality.
In the remote countryside, the Crown Prince runs into her, beating up her enemy. She is indifferent, but it’s love at first sight for the Crown Prince!

“Not good, Your Highness the Crown Prince, Her Highness the Crown Prince Consort used an immobilization talisman on His Majesty the Emperor, and His Majesty is currently eating dirt in the main hall.”

“Isn’t that normal? Who told that dog emperor to provoke my wife? I say it’s a job well done! Pour a bucket of ice water on him to cool him down!”

- Description from Novelupdates

There was a Senior Brother and a Junior Sister. One of them was transmigrated to this world and had cheats while the other was the reincarnation of a Great Emperor.