Nidome no Yuusha - Chapter 139 - Returnee, lamenting his helplessness

Damien reveals an ugly truth.His sister and only family, Ahara, leaves the house every midnight whilst he's asleep—a time that he soon discovers is when man-eating beasts named Rouges start hunting for prey.Unable to question her directly, he decides to investigate her and quickly figures that Ahara isn't human but rather, a vampire hero who saves them from beings like herself coming from a world she calls Gibbous—a place where entities like vampires, wizards, and beast shifters alike reside. What’s more, he also learns that the real reason behind his parents' death was the leader of the Rogues, who's rumored to have escaped after Damien’s father almost killed him.A series of fateful events lead to Damien’s long-lost power reawakening in him, and he finds himself with no choice but to return to Gibbous, a strange world where power means survival, and weakness leads to death. As such, Damien enrolls in an academy to train his newfound abilities with one thing in mind...Becoming more powerful.However, he soon discovers that the path to power is one filled with troubles and pain, and he isn’t alone in this lust for more at the academy. It’s a bloody competition against time and formidable opponents, and only those willing to sacrifice their comfort are the ones who can attain it.With a deadly foe lurking in the shadows somewhere and a strong desire to protect his sister, Damein has no choice but to fight.The only way is up, and he is going to be standing at the top of them all, ready to counter any enemy.

Her – a glutton without troubles or worries who crossed over and became a young fat chick with a deep vengefulness.

The more ruthless the Palace is, the more miserable the loser will end up—this he understands. But what he does not understand is, why the brother whom he lived together with peacefully in the past, would so heartlessly humiliate him today. Asking him to beg for mercy, asking him to succumb to his knees, and even… asking him to tactfully entertain him. “Yong Shan, ah, Yong Shan, as of today you are the one who qualifies to succeed as a Crown Prince, what exactly is it that you want?”

For the past 16 years, Yong Qi’s gaze was never set on him. Despite being twins with his younger brother, Yong Lin, Yong Qi has always been directing his smile and laughter towards Yong Lin, and to him, Yong Qi deliberately alienates him. He does not understand, they have the same features and looks, and he obviously is his brother too, but why won’t he be intimate with him… as if he is humiliating him. “Yong Qi, ah, Yong Qi, why won’t you understand, what I want is very simple…”

- Description from Novelupdates

Lee Seongjin, the strongest hunter who defeated the demon king.
He possessed the body of the pig tr*sh Third Prince, the Holy Imperial Family’s shame.

But the members of this family… there’s something strange about them?

‘Overpowered’ Holy Emperor.
‘Regressor’ First Princess.
‘Player’ First Prince.

Lots of trouble and lots of words
The story of the Holy Emperor and his children.