>>64308836Magic gameplay runs off a resource system using "mana". Land cards, which are usually around a third of your deck, are the main sources of mana. There are 5 colours of mana, and 5 types of "basic" lands whose sole purpose is to produce mana. Mountains produce red mana. "Nonbasic" lands may also do other game things or produce multiple types of mana, making them more attractive to use over their basic counterparts.
Those 5 types of mana pay for the costs of playing cards, and each color of card does different game things better that other colors. You need blue mana to pay a blue cost, and red mana to pay a red cost, and so on.
Blood Moon accomplishes two things:
- By turning nonbasics lands into Mountains, it shuts down all their other game uses they might have had.
- If your opponent was relying on their nonbasic lands to produce nonred mana, they're suddenly locked into only producing red mana, which locks them out of playing any cards that
need other colors.