I am an idiot.
ライティング
読書の
2779
本を読む
Synchro technically does exist... Since Crimson Dragon and its Servants (The Signer Dragons) fought the Earthbound Immortals 5,000 years before the events of 5Ds take place. The time gap between Yugioh and Yugioh 5D definitely does not exceed half a century or something like that.