[Despite his title, it's Queen Elsa you'll likely find within the castle of the Otherworld. Emrys is once again ignoring many of his duties to his own land, instead choosing to roam the places where the occasional visitors or even those who were born there get lost at.
Being who he is, he can easily sense whenever anyone's lost, or might need help. Even if no one requires assistance, he's happy to explore the lands, some corners of it unknown even to him, and to meet others living there. He might be bored by royal duties, but he loves this land - it is this, partially, what's driving him to push for an integration of the worlds. He wants others to be able to see it, and wants to find out more about the other lands in return.]
[Today he's wandering around one of the grottoes hidden near a lake (he knows other beings are usually llured by the water, and so knows to go to them to find others easily), in his usual, preferred humanized form.]