This also applies in reverse to the three Synchro Monsters automatically obtained before the match against Team New World - the player is supposed to not keep the cards and they will disappear if the player exits the Deck Editor with the cards not being in their Extra Deck or Side Deck, but saving a Deck Recipe that has any of those cards will let the player keep them
While we dont have full information yet about how the card works mechanically, theres plenty of room for speculation
Vren, the Relentless stops graveyard shenanigans, is hard to remove, and shits out Relentless Rat tokens each turn
Ancient Greece Greek mythology often explored transformation, fate, heroism, and changing identity
Protecting Toon World is essential, as its destruction results in the simultaneous destruction of all toons in play
During either players turn, Zoodiac Drident can detach an Xyz material to target a face up card on the field and destroy it