Elf Tensei Kara no Cheat Kenkoku-ki - Chapter 10Book 4: -2: Compromise

With a square halberd in the palm, and a red rabbit and horse under him, nowhere can the world go!

- Description from novelbuddy

Amidst a disaster, an orphan contracts a sickness.

In his waking hours, he is tormented by his ailment, but when he slumbers, there is infinite darkness.

One day, when he was five years old, a strange Fate Trickster appeared in his dreams. Ten years later, he dreams of becoming a lord. To do so, he takes a chance to trade his fate!

That day, Wang Zhong once again stood at the gates of the Tianjing Heroic Soul Academy. He was about to start a brand new life.

- Description from Novelupdates

What would you do if you were told you only had five years to live?Aster Mistral, suffering from an incurable congenital “disease” that saps life force out of his every breath, decided to fight with all his might. Waking up into the future, 2,500 years later, he embarks on a quest to find a cure for his ailment!“My target! To find the Panacea on the 1,000th floor of the dungeon!”Together with trustworthy allies, he forges a path of blood and corpses, building his foundation and increasing his level! However, he can’t stay in dungeons all the time, as he has a duty to fulfill.“To raise the human DNA average of the world, the government wants my seeds?!”Follow Aster on his laidback journey of fighting monsters, courting girls, escaping adversaries, and discovering secrets about himself!

Roy’s life was nothing special. The only thing commendable was the last few moments when he saved a mother and her child from a drunk driver.
…
It’s really an egg! Damn it, what kind of monster have I become? Did I fall into Hell instead of making it to Heaven??
Join Roy as he ventures through various worlds with the Custom Made Demon King System—a system that allows Roy to draw anything he can imagine and create it through exchanging souls!