As YouTuber In Third Person explains, Serena provides so much utility, a player can discard three cards, pick five cards from their deck, and force their opponents to activate their V cards with just this one card
As a bonus, ability, as if this card needs it, you can tap it and sacrifice ten nonland permanent to make all your opponents lose 10 life
All it does is give the equipper +1/-1 , and if it dies with Skullclamp on, you draw 2 cards
If a world permanent is on the battlefield, another one entering the battlefield will put the first into its owners graveyard
Both would later follow Cobalion to Pledge Grove to meet Keldeo
Timing is everythingyour Sigilyph needs enough energy to pull it off, and youve got to get it into the active spot