The Last Ronin [Teenage Mutant Ninja Turtles] Wolf Horror How do they know to

How do they know to fight like that

or sorcery card with converted mana cost less than or equal to the number of colors of mana spent to cast this spell

−X: Exile each permanent with mana value X or less that's one or more colors

Set: Core Set 2019 Prerelease Promos Type: Creature — Elf Druid Rarity: Rare Cost: {G}{G} Other Elves you control get +1/+1

Set: The Brothers' War Type: Legendary Creature — Human Artificer Rarity: Rare Cost: {2}{W} Vigilance

The Last Ronin [Teenage Mutant Ninja Turtles] Wolf Horror How do they know toSet: Teenage Mutant Ninja Turtles Type: Enchantment Saga Rarity: Mythic Cost: {4}{B}{G} (As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) I Destroy all creatures. II Mill four cards. When you do, return target creature card from your graveyard to your hand. III Whenever a creature you control attacks alone this turn, put three +1 +1 counters on it. It gains trample, lifelink, and indestructible until end of turn.