|Door||The Black Door|
The omega key was the first key to be crafted, in 1775. When Benjamin Locke was hiding in the caves with the revolutionaries, they accidentally opened the Black Door and some of the Children of Leng came out and immediately turned to Whispering Iron. Once Benjamin realized that regular steel was insufficient to hold the door closed, he crafted a padlock and key from the whispering iron itself. Later, the lock was modified to be part of the door itself.
The key was only used to obtain Whispering Iron, and no infestation of the Children of Leng was recorded until the Tamers of the Tempest made their attempt. After the events of that attempt, Rendell Locke vowed to make sure the Omega Key stayed hidden for the rest of his life.
After Dodge came back and started hunting for the key, it remained hidden until it was found in Rendell's cremated remains. Tyler Locke then attempted to hide it in his head using the Head Key, but Dodge (in Bode Locke's body) eventually gained possession of it.
Unknown, other than it opens the Black Door
The Black Door
(damaged) ...another dead & the...dore open againe...the things turned to irone...in our w...& I resolved to use them to crafte...hazzarded such a lock wood hold...long I worked in a fever'd...till finallie t'was cast &...oh how I feer'd! My har...in the gathr'd dark... straiked out &...held the dorr...beig'd God... Gonel...hold"
This key and it's counterpart, the Alpha Key, were created in reverse order. As has been stated, the Omega Key was created first, and the Alpha Key was created last, about 237 years later.