Back to the 70s: My Childhood Sweetheart Spoils Me Rotten - Chapter 76 - 75: Backing is Gone

To save a doomed fantasy world, I killed the main characters, then destroyed the game world, and fell into another timeline as the academy's top seat and rival to the protagonist.Now, I'm trying to save the world and steer it towards a better ending…But I'm the final boss.

Yo, Hi! I’m Frank, I made a deal with a demon to pay me some money for receiving a guest for a few days every week.
I had no idea about what I have done.
On May 1st, Conan ‘the God of Death’ came to my house. I was forced to let him in and we get involved in a criminal case.
On May 8th, Bruce Wayne ‘Batman’ came to me. I was forced to follow him to fight crime.
On May 16th, Hannibal Lecter, The Silence of the Lambs, came to my home. I can only say that I really can’t stand my guests.

- Description from Novelupdates

In a world of power struggles and betrayal, A hero was once a loyal warrior who dedicated his life to helping his childhood friend ascend to the throne. Through blood, sweat, and unwavering devotion, he paved the way for his friend's reign—only to be betrayed the moment his goal was achieved. His life was cruelly stolen, but fate had other plans.Instead of death, he awakens in his childhood once more, armed with the memories of his tragic fate. This time, he will not be the loyal shadow of a false friend. This time, he will seize the throne himself.Yet, this is not his story.Our true protagonist is an ordinary man who finds himself reincarnated into this world—not as a hero, but as an extra. A mere background character destined to meet a tragic end, a third prince whose death will serve only as fuel for the true villain's rise. Slated to become an undead knight under the fourth prince, the last and most terrifying villain of this dark tale, he must now defy fate itself.With knowledge of the future and a world filled with scheming nobles, ruthless warriors, and an impending catastrophe, can this forsaken prince change his fate? Or will he meet his destined end, only to rise as a pawn in the villain’s grand scheme?A tale of revenge, survival, and defying fate begins now.

“How many people have you killed? How many families have you destroyed? How many towns and cities have fallen because of you!?”“I don't remember.”The villain whom the main character was destined to defeat at the end of the novel. That was who I had become.There was just one problem...“Why am I a teenager!?”“Why is there a school acceptance letter on my desk!?”