I am the Demon king, but why do the Goddesses favor me? - Chapter 29: Hero’s festival

It’s said that the prince of virtue had almighty martial arts. It’s said that the prince of virtue had the most handsome appearance in the world. It’s said that the prince of virtue was brilliant. But all was legend! A fire ruined his wonderful appearance and his legs. Even the talented bride under their marriage agreement were replaced furtively. Ye Liu-li was his bad-luck substitutive princess. She went a long way to graduate from Medical University and had her internship with pain and joy. Who knew that in order to save a suicide patient, she fell off the building and crossed time into a “chessman” of prime minister. She had also been married to the disabled prince replacing her elder sister. On the wedding night, when most other couples were having their romantic night, she was thrilled. It didn’t matter. Revenge never came too late. She would never let go of any of them who entrapped her or harmed her.

- Description from Novelupdates

“On that day, Zach Harper died-” Or at least that was how it was supposed to be. I died. But there was good news, and bad news. The good news; I was reincarnated! Transmigrated into the World of Aethoria! Holy fuck, miracles do happen! But the bad news was, “Huh? What’s this?” ... [DING!] A New Quest has been issued:- Type:- SURVIVAL Name:- Quest To Becoming Stronger: Description: The {Great Calamity} is coming...Get stronger and survive. Duration-: ... Reward:- ... Penalty:- Death, ??? ] ... I had to survive.

“You might be my wife, but I shall not lay a hand on you.”

“Is that so? Then can I lay my hand on you?”

“……Pardon?”

***

Around 20 years in the future, the world is destroyed due to the invasion of demons. There’s only one way to prevent the destruction.

Marry the Duke known as the Monster and give birth to his child who will grow up to be the future warrior.

“Mielle, that marriage, I’ll do it instead.”

Yelena, who saw the future,
decided to get married to the Monster Duke and give birth to his child to save the world, however…

“Are we going to keep being idle like this?”

She thought she would be able to get it over and done with (?),
but her husband’s impregnable fortress-like defenses are beyond imagination!

“I told you to strip! Why aren’t you stripping?! Is it a part of your skin?”

Can Yelena safely give birth to the warrior and save the world in the end?