Nightveil Specter 4
Take a look at MaRos articles describing new sets - he does not just dump the image gallery and say let me know what you think - he describes the sets design goals, the mechanics, why they were chosen, how those mechanics were placed in each colour, the limited archetypes the set was designed around, some anecdotes about the design process, etc
Gates is very much a five-color strategy, and while Nine-Fingers Keene is great in those decks, it should not itself be a commander
But cracking good ones might be a challenge
With your palm up left hand strip packets off the top of the deck with your thumb and 2nd finger
Successfully mutating a creature in play does not make it a new creature entering the battlefield, even if you just turned a 1/1 token into a 6/6 flying trampler