Traveling Across France: Learning Magic with Zeref at the Beginning

[Decisive killing] [No system] [Invincible knowledge base] [Single female protagonist] Yun Yi traveled through the world of full-time mage and became an orphan, but he possesses Zeref's treasure trove of magical knowledge. In this era where humans are struggling to survive in the cracks of demons and monsters, while others are practicing elemental magic, he has begun to transform the laws of the world! Magic tool? The ring that Yun Yi made casually can swallow stars and spirits, increasing the speed of cultivation by fifty times! Magic? Destroy gods, destroy evil, destroy dragons? Sorry, that was a required course he prepared for his disciples. Power? Magic Association? Hunter Alliance? But a secular organization. The "Hades" established by Yun Yi is the final place of judgment in this world! Each of its demon legions is a walking natural disaster! They don't know that when the undersea emperor sets off a tsunami that will destroy the world, and when the holy city holds high the flag of hypocrisy... Yun Yi will rise from the throne of Hades and let the whole world understand—— Who is the real master of magic, the master of doomsday!