Once Demon of Catastrophes is on the battlefield it will be the biggest thing in the air, with the only thing holding it back right now being the additional cost to cast
For instance, here she is in an Abzan Adventures deck: Creatures (24) 1 Lotus Cobra 2 Scavenging Ooze 4 Lovestruck Beast 4 Murderous Rider 3 Giant Killer 4 Edgewall Innkeeper 2 Shepherd of the Flock 1 Polukranos, Unchained 3 Kazandu Mammoth Planeswalkers (2) Lands (25) Spells (9) Why Abzan
You have to remember that the term value is subjective when it comes to Magic The Gathering
Her ability is twofold, she exiles cards from your opponents library when your Elves or Faeries enter the battlefield, and then she lets you cast spells from that exiled pile for free if you have enough Elves/Faeries to match the mana value
You can tap a Pinger, shoot an enraged Dinosaur, and then get two triggers, so she is awesome for Pinger into Enrage archetypes
If left unchecked, it turns into a monster of a creature
