After Mistaking the Child for Mine, I Picked Up the Great Demon King

[A gentle, dark elf who flirts without realizing it, bottom x A calculating, obsessive demon king unicorn, top]

Lan Mier transmigrates into a Western fantasy novel as a cannon-fodder villain.

In the original story, the protagonist is the darling of the heavens, with the greatest talent and strongest magic. At a young age, he wins first place in a magical tournament held by the most prestigious academy, defeats countless demon kings bent on destroying the peace, and eventually becomes a figure revered by everyone on the continent.

As a young cannon-fodder villain, Lan Mier can't bring himself to oppose a promising protagonist like that. All he wants is to cling to the protagonist's coattails.

According to the timeline, the protagonist is also still a child.

Believing that it's best to latch onto the protagonist's coattails early, Lan Mier travels a great distance to seek him out, only to arrive just as the protagonist is driven from his home by his own people, branded a bringer of bad luck.

After going to great lengths to drag the protagonist, battered and hopeless, out of a garbage heap, Lan Mier can't help but stare in shock.

Where's your huge protagonist halo?!

*

With no other choice, Lan Mier has to make a living alongside the protagonist.

The two children clear a small patch of wasteland to grow vegetables, build a little home of their own, run errands, deliver letters, and take odd jobs, scrimping and saving every silver coin.

Lan Mier knows a thing or two about investment. Every bit of love he gives now increases his chances of being able to lie flat and live off the protagonist later.

So even though he's still growing too, he gives all the meat in his bowl to the protagonist, watching eagerly as the other boy eats it all.

At last, they've saved enough for tuition. Just as Lan Mier eagerly awaits the protagonist's dazzling performance at a competition watched by the entire continent, the protagonist summons an evil artifact and easily defeats his opponent.

In the original story, this artifact is blood-linked to the most powerful villain of all, the great demon king.

As he gazes at the magic energy spreading across the sky and the "protagonist" staring at him with bloodshot eyes, Lan Mier realizes in a daze...

Oh no. It seems he's got the wrong person...

At this point, the only thing to do is run!

*

When Erion was young, a wizard glimpsed his fate and said he would become a wicked demon king, destined to be defeated by the protagonist born alongside him.

Erion didn't believe it at first, but the wizard's prophecies came true one after another, until he was left near death, abandoned by everyone.

Lan Mier's arrival was also part of the prophecy. Driven by hatred, Erion chose to follow his destined path, deliberately impersonating the protagonist so Lan Mier would rescue him.

At first, Erion didn't care that Lan Mier was looking at someone else when he looked at him. He only needed Lan Mier's help to recover from his injuries, then he would repay kindness with betrayal, refine the artifact with Lan Mier's life, master dark magic, and do what a demon king was supposed to do.

Even in his dreams, Erion saw Lan Mier kneeling and begging him for mercy. But as time passed, Lan Mier was still crying and begging in his dreams, only now the setting had changed from a battlefield to a bed.

His unspeakable desires grew harder and harder to suppress. Almost impatiently, Erion revealed his true self, sadistically waiting for Lan Mier to look at him with fear and disgust.

Then he could imprison Lan Mier somewhere he would have no choice but to look at Erion alone.

But instead, Lan Mier grabbed his hand and pulled him along as he ran away.

*

Busy helping his childhood friend evade the real protagonist's pursuit, Lan Mier doesn't notice Erion's eyes turning slightly red as he watches him walk away, the corners of his lips lifting in a smile he can't suppress.

His eyes are filled with possessive desire.

*

Lan Mier (bottom) x Erion (top)

-

They start out growing crops and taking odd jobs to save money, then later enroll in an academy, level up, fight monsters, and compete in tournaments.

Childhood friends who grew up together. At heart, it's a sweet romance~

[Timestamped August 8, 2025. Evidence preserved; do not steal.]

Theme: To be added