The cards have naturally been assigned magic mana colors, with the Earth Crystal associated with green, the Water Crystal blue, the Fire Crystal red, and the Wind Crystal white
Sure, it can Fog creatures every turn that are attacking you or remove potential blockers, but its just downright cruel against opponents with Hangarback Walkers
(I'm not getting into how production makes cards, but how R&D handles the information.) Thus the first function of a card code is to let everyone know a card's rarity
1 foil showcase or borderless card, any rarity
Oath of Eorl I don't love the delayed monarch trigger on Oath of Eorl, as it gives your opponents a few turns to dig for a Reclamation Sage or another answer, but I do appreciate how well it protects itself