Is the seal of orichalcos real?

There is no real card called Seal of Orichalcos. The soul-stealing mechanic would be tricky to implement in real life.

For one specific tournament, some prints of the card were created by Upperdeck for that event. However these are not 'real' Yu-Gi-Oh cards in the full sense of the Word, despite being made by upperdeck, they were still fan creations and not real game cards.