Superstar From Age 0 - Chapter 575:

One day, a tower appeared in the skies of all the major cities…

She, the “godly doctor” of an assassin organization in 21st century, transmigrated into the body of Yun Family’s abandoned, good-for-nothing Ninth Miss. Good-for-nothing? Then she’ll let the world see what a real good-for-nothing looks like. Summoners are legendary? Nothing is impossible in this world! She’ll become the first Magical Summoner.

He, the third prince in Long Xu Kingdom and the mysterious, behind-the-scenes owner of Zhou Dynasty’s monopolized business, seemingly handsome and uninhibited, is actually brutal and merciless.

The world knows her as a sickly good-for-nothing and her standing is as low as a servant’s, yet she solely dominates his heart. Trickery, schemes, overbearing, seducing… an exhaustion of methods, all to capture her heart. The scheming couple supports each other, producing stories about enmity, love and win-win cooperation.

Read to see how they stand side-by-side at the peak of this extraordinary world.

- Description from Novelupdates

A 29 year old civil employment exam student wakes up in a blank white room and meets a baby angel. This baby angel informs him that he died in his sleep due to heart disease like his father and grandfather. Remembering his mom and their last conversation he says that he will take on a series of life and death tests that the baby angel offers him. From this point on he must put his life on the line and fight in the stage called ‘Arena’. And Every time he clears a test he will gain abilities and weapons to increase his strength. All to clear the tests and get his life back. This is his story of his fights in the ‘Arena’.

Entering Tokyo in the bubble era, in this strange era, the only familiar ones are Matsuda Seiko, Nakamori Akina, Kudo Shizuka…

- Description from novelbuddy