The real excellence of this card lies in the ability which allows you to draw a card every time your opponent does, as long as Diablo is exerted
Good synergy
high loyalty, produces a creature to protect himself, and generates card advantage
If you crack 100 FIN packs, you'll end up on average with around 21 FCA uncommons, about 10 FCA rares, and just 2 or 3 FCA mythics
The first combat phase language makes it sound like you can only get a single extra hit, but combat damage to a player means that if you successfully damage all three opponents with creatures that are strong enough, this triggers separate instances
Typically this is split between 23-25 land cards, and 35-37 creature, spell, enchantment and artifact cards