A thought crossed Wang Yi's mind, and he immediately received a system notification: "Ding! Would you like to consume 10,000,000 Chaos Energy to upgrade the Heart of Chaos to A-Class?"
"Yes!"
"Ding! 10,000,000 Chaos Energy consumed!"
"Ding! Congratulations, your Heart of Chaos has been upgraded to A-Class. Equipment slots +1, Durability increased by 400 points. You will receive a [Civilization Achievement]. Calculating..."
"Ding! Congratulations, your Heart of Chaos has obtained the Civilization Achievement [Four Great Inventions]. Through the Heart of Chaos, you can consume 1,000 Chaos Energy to create [Papermaking Mill Construction Drawings], [Printing Factory Construction Drawings], [Gunpowder Factory Construction Drawings], or [Watch Factory Construction Drawings]."
