Keystones are magical stones of significant power associated with the Ayleids. They are primarily found in the ruins of the Barsaebic Ayleid in Black Marsh. The keystones were created in the Merethic Era using the magic of the ancient Argonians, which the Ayleid slavemasters infused in the stones through torment and fear. As such, the keystones exert power over the Hist. There were also used in powerful Ayleid enchantments, such as magical barriers.
Modern research of the keystones is limited by the dangerous nature of the relics. Only certain individuals can handle the keystones without suffering from nervous breakdowns. The Kothringi in particular could handle them for any length of time.
- For game-specific information, see the Oblivion article.