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

How do they know to fight like that

among any of the creatures it's being blocked by or is blocking

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

Each opponent gains 1 life

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

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.