Back Then, I Didn’t Realize It Was A Big Win

A brief description of the manhwa Back Then, I Didn’t Realize It Was A Big Win:

Seo Yeon-woo earns a living by playing games, and in the hidden quest game he’s been given, he struggled for several months and received fragments of a cube as a reward. What are these cube fragments used for? Are these scammers? Give me back the time I’ve wasted! But something amazing happened when the cube came into my hands. “You have become the owner of the ancient magical weapon ‘Kigantes Dark’.” Is this my turning point in life? Did I hit the jackpot? This is the story of Seo Yeon-woo, a survival-type gamer, and his adventure with the ancient weapon, Kigantes Dark!