Looks like Duel Links has finally jumped the Shark.
Duel World ZEXAL gets its first big event which is the Numbers appear event were you obtain Number Tokens to use to duel Reginald Kastle aka Shark. To obtain Number Tokens all you have to do is duel in duel world and after every duel you obtain some amount of tokens to use to duel Shark at the Event Gate. Dueling Shark at the Event will all you to obtian Number 17: Leviathan Dragon a very good Generic Rank 3 monster. Most of Sharks drops are recycled from Mako Tsunami.
Duel Links has added the ability to unlock a new Reginald Kastle by completing Challenge 3 on/after October 30th at 6:00 GMT +1(1:00 EST). Shark comes with the skill Monarch of the Deep Sea: Number 32 which at the beginning of the duel adds Number 32: Shark Drake to your Extra Deck.