Based on multi-metaverse, ONSTON is a virtual world where users in 3D avatar with varied NFT objects can enjoy multifarious games and do economic activities. ONSTON will have multiple metaverses interconnected each other so the users can enjoy various contents. NFT Object used in various different metaverses can be transformed for value exchange and use in the ONSTON Marketplace via ONSTON Creator Tool. The integrated NFT objects have new values, providing users with higher value and higher ideals. Through this, users can own the items in real sense.