At the beginning of each end step, if you control no creatures, sacrifice this enchantment and return all cards exiled with it to the battlefield under your control
Because of this, the Enchanted and Legendary rarity cards are appearing in many online marketplaces already and several have been valued very highly, although market values are still fluctuating regularly
But its second ability is what makes it shine because your proliferate triggers now give you tempo and value at the same time
There are a couple of decent questers with high Willpower and high lore value in this deck, like Robin Hood, Daydreamer and Starkey, Devious Pirate, but more often than not you'll get more value out of steadily questing with an unanswered Don Karnage than you will with an intimidating late game bomb
Legendary Creature - Sphinx Urza, Lord Protector Artifact, instant, and sorcery spells you cast cost less to cast
This might be a better direction to go for mana base reasons