Marriage contract: Genius baby's belly daddy - Chapter 2563

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!

One day every human on the world suddenly receives a mail claiming to enact the World Salvation Project. Half in doubt Kurosaki Shion, a diligent university student and loner, follows the mail’s instructions, becoming one of a million Demon Kings governing his very own Domain in the new world.

*** This is a post-apocalyptic story containing many fantasy elements. It is a somewhat dark tale following Shion as he grows while aiming for the unification of the all too sudden new world. It has many game-elements bolstered by strategical thinking while at the same time providing funny moments and romantic encounters.

I, Zhou Mingrui, transmigrated to an alternate world and became an ordinary little skeleton.

I received a system at the start which made me more powerful whenever I killed an enemy.

I can draw the health, mana, and other stats from the dead.

Every 10 levels, I can also awaken a talent.

Level 10: The Book of the Dead.

All incantation time for Undead Spells is shortened by half, and their effects are increased twofold.

Level 20: Skeleton Armor.

Build weapons and armor that are suitable for the user using skeletons. Weapons can be upgraded when the user’s level increases, while the armor can be upgraded to increase its immunity against all negative effects.

Level 30: Soul Summoning From River Lethe.

The user can summon dark creatures. The maximum number of summons increase with the user’s level. The summoned creatures’ stats are increased significantly.

…

I, Yan Wuyue, leader of the human. I am crowned the [Goddess of Savior] by the people of this world.

I reincarnated 30 years before the apocalypse. I have to get stronger in order to change history and save humanity.

So, my initial summon monster is extremely important.

I thought I could sign a contract with a dragon, a phoenix, an angel, or some other creature from the ancient myths.

But when that ordinary, unassuming little skeleton fell from the sky…

I was plunged into despair.

Even the most ordinary sorcerer could summon a ton of these things with a wave of his hand!

Su Ran, a music prodigy, woke up transmigrated into a book.

At that point in time, the main story arc in the book had already been completed. As a villainess female supporting character, not only did she need to take over the original owner’s pitiful life in poverty, she also gained an instant son right at his rebellious period.

Ten or so more years from then, the son would turn into a twisted, evil villain. He would appear in one of the extra chapters to pick on the male and female lead’s children.

***

Su Ran: Son, you shouldn’t be too outstanding.
Su Han: Why not?
Su Ran: ’cause you will be killed.

Su Ran: Son, would you like to learn music from me and become a zen, little fairy boy who only needs to drink dew.
Su Han: No, I want to go into business so I can support you.

- Description from Novelupdates