@SuperSnekFriend @ArdainianRight @EneP @locagainstwall @supersid333
It goes further than that. In the original manga, the card was only supposed to be around for one story arc before it went to another game, with Duel Monsters only being included since he liked MtG at the time. Takahashi simply retooled it around Duel Monsters after seeing how popular it became; he was able to have the final battle in the manga take place in D&D like he originally planned though.
Also, Bandai had their own version of the yugioh card game before loosing the rights to Konami.