I needn't carry a stone around the world to understand its hardness. I need only know it is a stone. 
Demon Knights #20 is an issue of the series Demon Knights (Volume 1) with a cover date of July, 2013. It was published on May 8, 2013.
Contents
Synopsis for "The Stone Door"
In Themyscira, Shining Knight suffers from nightmares of her own vampirism while Exoristos is invited to return to her homeland. In the city's library, the Demon Knights determine the Holy Grail's possible whereabouts - an uncharted island in the middle of the Mediterranean Sea. They set sail and, after two days, find a fleet of sunken ships. Xanadu discovers and dispels an invisibility enchantment and a hidden island appears.
On shore they are almost immediately attacked by a giant octopus named Architeuthis. Once the monster is destroyed the group finds a stone door adorned with glyphs. They determine that the glyphs are of Merlin's design and one in particular represents the Holy Grail.
Appearing in "The Stone Door"
Featured Characters:
Supporting Characters:
Antagonists:
- Cain (In dream sequence only)
- Architeuthis
Other Characters:
- Khronika (Single appearance)
- Vanguard
Locations:
Items:
Vehicles:
Trivia
- Given access to Themyscira's vast historical library, Vandal Savage went directly to the how-to section to find and read Kama Sutra.
