Butcher Demon - Chapter 44: Mechanized Heavy Armored Infantry.

So here's the pitch: I got reincarnated with Mangekyo Sharingan.Sounds overpowered, right? Instant win button?Except I can barely keep it active for thirty seconds without feeling like my brain's being microwaved. My chakra reserves are pathetic. My combat experience is zero. And the system that gave me these powers took one look at my situation and said “good luck” before fucking off into hibernation.Oh, and the Hero Killer—the guy who murders heroes for not being “worthy”—just decided my mom wasn't good enough. She'll never walk again.I know when he'll strike next. I know where. I've got exactly four weeks to train.Four weeks to go from “can't throw a punch without tripping” to “can survive a fight with a serial killer.”The smart move? Stay out of it. Let the pro heroes handle it.But I'm fifteen, angry, and apparently making life decisions with the wisdom of a shounen protagonist.At least I'm in General Studies. Low expectations.What does being a hero have to do with revenge anyway?

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.

Li Yuanqing transmigrated and became the crown prince of Northern Kingdom. He was sent to the borders, after his cultivation and meridans was crippled, because he refused to marry a princess and was not allowed back into the palace ever.

Just then, the Hundred-fold Sign-in System was activated!

Outside his house in the Wilderness, he signed in and received 100 Replenishment pills!

Beside the lake of the Wilderness, he signed in and received 100 Marrow Cleansing pills!

Among the warriors of Myriad City Kingdom, he signed in and received 100 Heavenly Skill manuals!

…

Li Yuanqing had thought that if he just signed in silently and received the hundred-fold reward, he would be able to watch over his younger sister until she became the ruler of the kingdom and until he became invincible.

But he had never thought that one day, the queen of Myriad City Kingdom would come to meet him!

“I am willing to use Myriad City as my dowry. Will you marry me, Your Highness?”

Li Yuanqing did not know what to do when he looked at the queen smiling beautifully before him…

This is a story of Xia An, a transmigrator from the end of the world, who transmigrates into the body of a cannon fodder who was the mother of the villain.

- Description from Wattpad