In Magic the Gathering how does protection from a color work?

Answer 1

'Protection from..' means the card can't be damaged, enchanted/equipped, blocked or targeted by something that it is protected against.

So if a card has protection from red;

- It can't be dealt red damage. Targeted sources of red damage can't target it, it will ignore red damage from creatures it blocks, and even non-targeted damage is ignored, from sources such as Pyroclasm).

- It can't be enchanted by a red aura, or equipped by an Equip card that has been made red by another card. Auras normally target, and the protected creature is therefore an invalid target, but some abilities can move Auras from one card to another without the Aura targeting it. In these cases, the Aura will be destroyed, same as if a creature is equipped with a red Aura, and then gains Protection from: Red.

- It can't be blocked by a red creature when it attacks.

- It cannot be selected as a target by any red ability, be it a spell, monster ability, even a Planeswalker power.

Protection does not protect from indirect (non-targeted) effects unless they are damage. So a Protection from: White creature can still be destroyed by Wrath of God, and a Protection from: Blue creature can still be returned to hand by Evacuate.

Lastly, if a source is multi-coloured, you only need to be protected from one of those colours. A Protection from: Red creature is protected from thing which are Red/Black for example.