
Double strikeDouble strikeDeals both first-strike and regular combat damage., vigilancevigilanceAttacking doesn't cause this creature to tap., hastehasteCan attack and use tap abilities the turn it comes under your control.
Whenever The Herald of Numot deals combat damage to a player, create a Numot, the Devastator token card and shuffle it into your library.
Numot, the Devastators you control have vigilancevigilanceAttacking doesn't cause this creature to tap. and hastehasteCan attack and use tap abilities the turn it comes under your control., and the "legend rulelegend ruleIf you control two or more legendary permanents with the same name, you keep one and put the rest into the graveyard." doesn't apply to them.
Hover an underlined rule to see what it means.
Read from the rules text. A card that enables a keyword makes or is the thing; a card that rewards it gets better when you have it. Two cards interact when one enables what the other rewards.