This is how the card reads:
[When this card participates in a challenge, you may choose a "Hollow Bastion" card from your discard pile and put it in your hand.]
Now when I read this card for the first time, I believed what others did most likely; that this allows you to search your discard for Hollow Bastion "themed" cards. For those unfamiliar, that means cards that read Hollow Bastion next to the card name. This would have Leon make ALOT more sense and have him be much more playable.
But from what I understand, they have ruled that Leon's text allows him to only search for Hollow Bastion world cards. Please fix this ruling, and allow him to search for Hollow Bastion themed cards instead. It isn't like it's a broken effect either. And even if you were to use the current ruling to help a World Racer deck, why on earth would a WR want to enter a challenge? Again, it doesn't make sense. The text should be taken as I first described.
Please fix this card, for Leon's sake.