“Lethal Damage” is a term you often hear in combat. It’s a term you might hear if the attacking creature has trample or when multiple creatures are blocking the same attacking creature. So in Magic term, what does “lethal damage” actually mean?

Lethal damage is the amount of damage it would take to destroy the creature. Usually, this just means looking at the creature’s toughness, but you also take damage that’s already been dealt and currently marked on the creature into account. For instance, if you Shock a 4/4, then it’s a 4/4 with two damage marked on it, so two more damage would be lethal for it.

And that’s it. You don’t take anything else into account. Things like protection, indestructibility, and damage prevention effects don’t matter when it comes to assigning lethal damage, you just look at the creature’s current toughness and damage that’s currently marked on the creature.

For example, if I attack with a 5/5 green trampler and you block with a 2/2 creature with protection from green, my trampler can assign two damage to the 2/2 (since two damage would be lethal damage), and I can assign three damage to the defending player. The damage that I assigned to the 2/2 will be prevented, but that doesn’t matter. What matters is that the creature was assigned what would be lethal damage, so I’m allowed to start assigning damage to the defending player.

You get the same situation if the 2/2 had a damage prevention shield around it instead. You only need to assign two damage to the 2/2, and you can assign the remaining three damage to the defending player. You can choose to assign more to the defending creature if you want, but it’s not required.

So remember, when dealing with lethal damage, just look at the creature’s toughness and the damage that’s been dealt to it this turn. You don’t need to take other effects into account that might increase or decrease the damage that would be dealt to the other creature into account.

Today’s Rules Tip written by Nathan Long