Maybe Terra will allow Enigmatic Incarnation to shift some of its maindeck cards towards specific pieces that improve bad matchups, but thats tough to say at the moment
The Pokmon Company engineers pull rates and scarcity tiers to create structured demand across different collector segments
You gain bonuses from putting cards into your graveyard if you descend, and then you can use those cards to collect evidence further gaining optional abilities or effects
The real strength of the card, however, and why it plays so well lies with the fact that Edgars ability to make Vampire tokens each time you cast a Vampire spell triggers even with Edgar in the Command zone
Devil provides disruption as well making things like sac lands, clue tokens etc
My last two choices are so good, they were reprinted in the Doctor Who commander decks, but these cards are originally from Modern Horizons 2 and Amonkhet