The rarity of Tome of the Dread Compact is Mythical. At this moment the item is available for trade.
Tome of the Dread Compact is a skin for Warlock. The skin was added to the game on May 14, 2018, it was created by Graff.
Tome of the Dread Compact is currently one of the most popular skins, but it is rarely seen in the game due to its high price.