mtg cards with friends forever How does Partner work in Magic: The Gathering? When that creature dies this turn oracle:friends oracle:forever) cmc<=2 · Scryfall

Running a companion in your deck comes with the disadvantage of specific deck build restrictions outlined on each companions card text

Note that you can do that the turn you drop it

This is another good way to help your collection out

There are of course exceptions to this

its restrictive casting cost allows the designers to give it an enormous amount of power for a five mana card

While playing Sylvan Library in a multicolor deck might sound strange because it only grows green creatures, if you look at a Gruul Aggro decklist, you'll see that outside of Bonecrusher Giant (which we can consider a removal spell), the list is almost exclusively green