You can make Dimir or Rakdos work just fine, but you wont have the raw self-milling power without using green
If youre looking for the perfect capstone for a green swarm deck, this card should definitely be in your sights
Eventually Wrenn will threaten to ultimate if not respected, which nearly always results in winning the game either by having nearly unlimited interaction, or a pile of Lightning Bolts
There are also a few more tidbits from the box and blurb: Where will you fight Ursula: at the site of your first encounter , or at her lair, where her powers are the greatest? , She has entangled many familiar glimmers
When in your graveyard this faerie can serve another purpose
TCG sets, with some thinking that this was done to avoid legal issues with Wizards of the Coast's Magic: The Gathering