You activate one of the Elven cards from your Deck (listed below) during your opponent's turn, depending on what you need
Retreat If your Active Pokemon has taken severe damage and you want to preserve it for later use, on your turn, you may Retreat it back to the Bench
C Common Crossroad Sonic Chick X EARTH Level 1 [ Winged BeastEffect ] ATK 300 DEF 300 If a Tuner(s) is sent to your GY, even during the Damage Step: You can Special Summon this card from your GY (if it was there when the monster was sent) or hand (even if not), but banish it when it leaves the field, then if "Junk Warrior" or a monster that mentions it (except this card) is on the field, you can change all monsters your opponent controls with 1900 or more ATK to Defense Position, also for the rest of this turn, you cannot Special Summon from the Extra Deck, except Synchro Monsters
A popular variant of this deck swaps out some Snake-Eyes cards for the Fire-King engine
But as a result, most of the campaign decks from Duel Monsters all the way to ZEXAL remain unchanged, meaning that if youve already played through the previous game, you can do it all over again for much of this one