This is mostly because Skysovereign has developed into an odd Pioneer staple thanks to Karn, the Great Creator tutoring it from sideboards in Mono-Green Devotion and Greasefang, Okiba Boss decks using it as a secondary payoff alongside Parhelion II
When this creature leaves the battlefield, the exiled card's owner creates an X/X blue Illusion creature token, where X is the mana value of the exiled card
Cards like Old Gnawbone and Ancient Copper Dragon produce a huge load of Treasure, and its not hard to have 10 Treasures in a dedicated deck
To add some extra chaos into the mix, Bothersome Quasit prevents goaded creatures from blocking
So even with a little quick Energy acceleration, a Lost Remover, Crushing Hammer, Claw Snag , and a Sharpen Claws could be enough to cripple CMT for a few turns while you further setup
Yugi Muto and Seto Kaiba, the protagonists of the Yu-Gi-Oh