It appears that Nintendo has now trademarked “Hyrule” in three different regions, according to a discovery by NeoGAF user Rösti. Now, at first glance, it would appear that the trademark on the familiar name would be associated with the recent title, Hyrule Warriors. However, the Wii U spin-off has been out for about a month in the US and Europe already, and even longer in Japan. It seems somewhat unlikely that this trademark relates to an already released title, or a name change of the game.
So, what could this mean? Perhaps Nintendo is planning to do more spin-off titles in the same vein as Hyrule Warriors; the title may have sold well enough to warrant a sequel. On the other hand, perhaps the trademark indicates that Nintendo may want to branch out even further than Hyrule Warriors and create other games with the “Hyrule” name.
In any case, the trademark is fairly interesting, and we will have to wait and see what Nintendo has in store for Link and company.