Murkfiend Liege has one of the best secondary effects for any Lord creature. During each other player’s untap step, you can untap all green and/or blue creatures you control, including the Liege himself. Even though the Liege doesn’t benefit from his own stat boosts, he does get to untap. In Commander, you will have many creatures of hybrid mana costs, and as long as there is a single blue or green mana symbol in its mana cost, it will get to untap. In a Commander deck like the 2013 pre-constructed Evasive Maneuvers product, in which Murkfiend Liege is featured, being able to untap your creatures is extremely powerful to be able to use their tap abilities after each of your opponent’s turn. Also, your creatures then are open to block, as well, making it possible for you to swing with creatures that you otherwise would not have.
While Seedborn Muse or Prophet of Kruphix are each more powerful than Murkfiend Liege, the added boosts in power and toughness alone make the liege a must in any deck that runs both blue and green and is creature-based. It’s a solid card that needed a reprint for a long time, as it was in the now long out-of-print Eventide set.