Whenever an opponent discards a land card, add to your mana pool
The colorless, noncreature Firewalker isnt quite as strong as the Kor himself, but it does a great impression for those decks that cant run Firewalker
So I think that we may fall prey to board stalls in which the creatures youre eternalizing are just not going to be able to compete with with the rest of the table
They only cost anywhere between one and three mana, and they'll stay on the battlefield until destroyed, bounced, or sacrificed
This can make you the de facto inevitability baron and make every long game basically approach impossible for the opponent
For instance, the Final Fantasy crossover includes double-faced cards to represent iconic characters, minigames, and story moments