BTTH: From Genius to Invincible - Chapter 182 - : Black Flame Change

The frail and sickly Wen Jiexi had always wanted one thing: a healthy body and like a dream come true, one day, she was selected by the system!

System: The amazing me shall grant you a strong physique and divine strength! However, you have to maintain your health through monthly missions! If you fail to complete them~well, then you’ll stay as a female King Kong, forever~

Wen Jiexi: What?! Will I no longer be able to live my life freely again?!!

Mother with an alarmed expression: My frail daughter is actually trying to do the most sit-ups possible?!

Father made a strange face: My delicate daughter ran on the treadmill for an hour?!

Brother’s expression crumbled: Can anyone tell him how his cute little sister who is as precious as a delicate white flower…was actually able to use one punch to break a sandbag and smash a hole through the wall!!!

Through a series of unexpected circumstances, she was pulled into the entertainment industry and became a female martial artist!

Female Fan: Our darling Wen is the most awesome! She’s even more handsome than a man!

Male Fan: The girls today are so domineering! To be able to throw away all of one’s shame, I want that feeling too!

The frozen expression after being hugged by the princess from behind: …..

Wen Jiexi held up a hand: No, no, no! It’s not like that!

- Description from Novelupdates

Waking up, Kim Hajin finds himself in a familiar world but an unfamiliar body.

Akira Kuromiya is just an average high schooler who gets killed by a robber. He wakes up and is now a chicken!? Even worse he becomes the familiar of a girl who's apparently the heiress of a powerful clan.

That was for a short while though, as he was abandoned and woke up to find out he, now she, is trapped in a deadly magical forest with all sorts creatures trying to kill her.

The world she finds herself is one of magic and monsters like the manga she's been reading. Akira, now Hinotori is trying to live her life as a chicken in another world!

Have you ever thought that the state of the world as it presently is, could revert to the laws of the ancients? When a series of strange incidents beginning with the disappearance of his friend led Luo Yuan to question the possibility of an apocalypse, he becomes embroiled in the midst of a global-scale chaos.