It adds tutor effects to the look at the top X cards in your library, you may reveal a card (land, nonland, etc.) and put it into your hand effect
As a companion it would be ubiquitous in any blue-red-X deck given the formats singleton nature, which gives those decks an extra card for free without any additional deckbuilding costs or restrictions
Using Magic 's recent Commander Brackets model for ranking decks, I'll tell you where the Final Fantasy decks fall, and what levels they can likely compete against
If Neva leaves the battlefield while it has an Aura you control attached to it or at the same time as another creature with an Aura you control attached to it, its ability won't trigger for those enchantments unless they were destroyed by the same effect that caused Neva to leave the battlefield
Dig whatever copies you have from your bulk and sell or trade them away now while prices are high, assuming you're not interested in playing the deck
However, its ability decreases the mana needed to cast Dragon spells by one
