The Mighty Thor by Matt Fraction Vol. 3
The construction of the new city of Asgardia reveals a cave, sealed long ago by Odin. When the ever-impulsive Thor smashes this tomb open, he frees the Mares - a race thought mythical even by the gods - who begin to prey on his dreams...and those of all in Asgardia and Broxton! Elsewhere, the Enchantress takes advantage of Dr. Don Blake's desire to be a god once more to unleash the dread new companion she calls her Keep. With only a bookish elf and a tormented Goth teen for allies, the Odinson must face his greatest fear in a dream from which he cannot wake. But what price will he - and a repentant Blake - be willing to pay to save the day? And who...or what...is the Deconsecrator? Collecting THE MIGHTY THOR #12.1 and #13-17.