Alirios turns up with his very own mirrored visage - a token complete with the same stats, but reversed
Imposter Mech is an excellent card, though not nearly as good as the others
If the creatures are too much to handle, it's good to use the creature destruction effect, and if the battlefield is manageable, destroying all lands is the way to go
Aside from being a human, which is a very relevant creature type in Commander, Modern and basically every other MTG format, Esper Sentinel is good because it reads: Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays X, where X is Esper Sentinels power. Its a bit like Rhystic Study, but the cost can be far higher if youve got things that make humans stronger or you can put +1/+1 counters onto Esper Sentinel
The set is especially replete with powerful instants and sorceries and payoffs for casting them