Harry Potter: A Certain Ancient Rune Professor of Hogwarts (TL) - Chapter 27

Enemies always meet on a narrow road and when they meet war breaks out.

They met as kids and fought but Zi Han lost.

They met in the army as recruits and even then Zi Han lost.

He lost again as he remained a sergeant while Yi Chen was promoted to the position of Marshal.

Even when his dark history swallowed him whole and shifted allegiance to become the Universe’s most infamous assassin he still lost to Yi Chen.

Zi Han, “Damn it! Why won’t you let me win.”

Yi Chen, “I can let you win in bed if you like?”

Zi Han, “……”

When did enemies graduate from rolling in the dirt fighting to rolling in the sheets….. fighting? That’s the million-dollar question.

.....

Throughout this current life of mine, I will pay no attention to my past lives, nor will I seek future lives. I wish to live vigorously, to pay back debt of gratitude and fulfill duty to avenge, to defeat valiant heroes from all species, and to proudly laugh at all the Gods and Demons of the Six Path of Reincarnation!

- Description from Novelupdates

Saying 5000 year-old-dragon has an impressive ring to it, yet that dragon was an extremely harmless, herbivorous being. However, because of his uselessly giant figure and scary appearance, he was mistaken for the Demon King’s executive and provided by the nearby village with a sacrificial maiden.

Fundamentally cowardly and timid dragon tried to send her away, but the extremely enthusiastic sacrifice didn’t want to give up. Inevitably, he lied: “Okay, I just ate a small portion of your soul, so you can go back already”, but the maiden with outrageous assumptions has misunderstood that she became the dragon’s kin.

Then, out of all things, she began to manifest strange power on the basis of her wrong assumptions – in turn, the helpless dragon, by some mistake started a rebellion against the Demon King.

Rebellion or whatnot, he wasn’t even his subordinate in the first place.

Dumbledore always believed Voldemort was the greatest threat to the wizarding world until a thousand-year-old vampire showed up at Hogwarts with the deed in hand—“A thousand years have passed, and Hogwarts' lease is up!” said Dracula. “Headmaster, you wouldn't want your students to be homeless, would you?”“What do you want?” Dumbledore asked gravely.“Anything interesting.”“Well, I think the position of Defense Against the Dark Arts professor is quite interesting!”...And so, Hogwarts gained a professor who couldn’t be dismissed.McGonagall: “Albus, I don't think Professor Dracula's teaching is suitable for the poor children!”Dumbledore: “There's nothing I can do, no one can fire him.”...Draco: “My father is a governor, I'll have him get you fired!”Lucius slapped Draco on the head, “Mr. Dracula, Draco speaks without thinking. Please, don't fire the Board of Governors!”...This is the story of a vampire who lived too long and found amusement in the wizarding world out of sheer boredom.