The negation power of Royal Decree extends pretty far, from being chained to the activation of Mirror Force or Sakuretsu Armor, to effectively Trap Jammering the opponents tricks, to being activated in response to Breaker the Magical Warriors effect that was targeting your Call of the Haunted, which in turn was keeping your Chaos Sorcerer alive
If the target nonland permanent is an illegal target as Anguished Unmaking tries to resolve, it won't resolve and none of its effects will happen
Lightning Storm and Evenly Matched are legendary board-breakers, but their synergy with Endymion is not perfect, as you cannot activate Scales while trying to draw into them, which makes the follow-up harder to achieve
Venusaur-EX Grass HP180 Basic Pokemon [G][C][C] Poison Powder: 60 damage
As many players pointed out in the comments, we have a few tools for such a deck already
(Put the top three cards of your library into your graveyard.) Whenever a creature dies or a creature card is put into a graveyard from a library, each opponent loses 1 life