Regression Guidelines For the Supporting Character - Chapter 123:

In 1177 Jerusalem, Ethan Caldwell awakens as the leper king Baldwin IV, blending modern ingenuity with medieval valor. Introducing hwachas, windmills, and a revolutionary crossbow, he leads a crusade to conquer the Sinai, outwitting Saladin and transforming the Crusader states.

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

A war goddess was reborn and obtained a Mutual Separation agreement.

She only wanted to remove her armor, return to the countryside, and marry an honest man.

Perhaps she would have three children, and they could live quiet lives farming and weaving.

By chance, she joined a refugee group and met a man who was adept in both the pen and the sword.

She ventured with the refugee group since spring until winter.

The man was very protective of her, and she figured it would be nice to marry him. He had strong arms, so he could surely plow large fields.

They could raise their children together and live happy lives.

However, who knew that the man was actually a dragon?!

Oh well, one must be content with the partner they had chosen, so she shall soar with the dragon!

The war goddess donned her armor once more and dominated the battlefield with her man! The emperor’s walls, countless soldiers, and vicious schemes.

She feared nothing as long as she stood beside her husband.

Just like that, they accidentally charged into the palace with their army.

Sigh, she had only wanted to bear three kids and live peacefully.

The man pressed her against the wall and asked in a low voice, “You want kids? I’ll satisfy your needs.”

Being able to see into people's past has no real appeal for the teenager this story is about, letting him use it only as amusement and to show off when he was drunk.Never watch into someone's past beyond a superficial level.Never try to find out more than you should.NEVER. EVER. LOOK. INTO. THE. FUTURE.But everything changed the moment he was forced to look into the future, was forced to investigate a murder, and was forced to make the acquaintance of the victim's twin brother('s fists).The more time passed, the more it appeared that the primary reason for this murder wasn't a local problem, but a global one.This single, marred corpse was the beginning of a threat that would shake the world.(MC looses a screw when he enters the prison)BL, first-person view; MC is shuo (perhaps even a reversible couple); love interest falls in love first; both MC and ML are straight, mutual bending, Enemies to Lovers