We'll take the time to tell you what you can and can't do with them
The insectile Speedbrood is the most devout of the bunch
If a creature or permanent is destroyed after resolution (and that is one of the bonuses associated with kill spells-their flexibility, because you only have one chance to counter), then the owner of that spell, while down-hearted knows that he or she at least got to play the darned thing
Going through Magic 's existing suite of resource mechanics with that in mind, energy counters were a great fit
This set is going to be legal in Standard until 2029 at the very least, so it is absolutely worth getting familiar with these cards as quickly as possible
Theres also a social benefit: The Ur-Dragon and Miirym have reputations as must-kill commanders because they run away with the game, a stigma which Ureni lacks