I Became the 1st Floor Boss of the Tower - Chapter 78: Sudden Attack

Reborn into the world of Yugioh, it's natural if my goal is to become the best duelist!

Ding!『You have acquired the skill: [Universal Language] – All tongues shall now bend to your understanding.』『You have acquired the skill: [Dimensional Exchange] 』『Item Detected: [Gold Coin x50] 』Initiating Currency Exchange…Exchange Rate: 1 Gold Coin = $1,000 USDConverting [50 Gold Coins] → [$50,000 USD].....Kael Lancaster grew up believing his family was ordinary—until he discovered that his estranged grandfather, Theodore, was a multi billionaire.Struggling with his family's debts and uncertain future, Kael decides to approach his grandfather and move into the Lancaster estate, becoming the old man's caretaker. For two years, he endures the family's contempt and Theodore's cold indifference, clinging to the hope that his loyalty will one day be rewarded.But when Theodore dies, the will delivers a brutal blow: Kael inherits nothing.Or so it seems.However, His grandfather had left him something else.A portal through which he could travel to another world—Kael can trade between worlds, amassing power beyond imagination.

A world filled with heroes with superpowers. A world attacked by calamity fiends. A modern world filled with wonders and dangers.

Shi Xiaobai, a child from normal Earth, walked into such a world, proclaiming to be its king. But at the first signs of danger, he is forced to make a choice, one which he cannot refuse for time would repeat, making him face the choice again.

He is not humble nor is he modest, but neither is he delusional. Yet, the Absolute Choice seems to make fun of him. Will the joke be on him or will he laugh at his opponents? There will be many watching his escapades, and there will be some joining him in his adventures.

To see through the world and to grasp its truth, that is the destiny of the King.

- Description from novelupdates

I finally managed to kill the demon lord.