Here’s a little hack that you can do on Yugioh Duel Links for your Smartphone. So far, I’ve tested this to work on my Android Phone. I’m not sure if it’ll work on an iOS, but considering its made by the same company (Konami), I think it should.
Anyway, this cheat allows you to duel Rex Raptor with Rex Raptor. Normally, this is not possible. If you play as Rex Raptor, Rex Raptor won’t appear in Duel World, so to make him appear, you need to play as a different character — Anybody as long as its not Rex Raptor.
To battle Rex Raptor using Rex Raptor, all you have to do is select a different character. And when Rex Raptor appears on Duel World, switch your character to Rex Raptor.
…And viola! You can now fight with a Rex Raptor doppelganger. This trick should also work with other characters (ie. Yami Yugi vs Yami Yugi, Joey Wheeler vs Joey Wheeler, Mai Valentine vs Mai Valentine, etc.) This should work, at least until Konami patches this bug.