According to the Shroud MTG rules, it interacts with other game mechanics in several ways
Menace is a great keyword to add to the mix when youre going wide: Your opponents need twice as many blockers, or they just take extra damage
Pull more lands into your hand for +1 Loyalty, play them tapped to the field for zero, create a creature token with toughness equivalent to the number of lands you control for -3, and return all permanents to your hand, while removing your maximum hand limit, for -8
Theres really nothing Derevi cant do, and if Im honest, its probably only this low because people feel dirty playing it
Theres also ChromanticoreChromanticore, which is just one of the coolest creatures ever printed