On the play I keep if my hand has any threat or two or more cantrips
However, there are potentially better cards with similar abilities, such as Bronzong from the same set, which offers a more consistent energy acceleration option
Ursaring is classified as a 2-Diamonds card in the Wisdom of Sea and Sky set
Binding is much too slow comparatively, so one should be focusing on what they can abuse by milling over six cards for only two mana
And double crisis Sealed blisters and sets of double crisis in english and japanese: I do have probably a full set of double crisis (I opened a lot when they came out) and maybe in the far FAR future I will attempt to complete a graded set of them, but for now I want to focus on the humans in the teams and any cards I can find with their faces on
If you mean 'challenging' other characters, or glimmers, in play Steel and Ruby are good at challenging and can get benefits for banishing opposing characters during challenges