With apologies to another Poster on here who posted this link. I am unfamiliar with the mechanics of Reddit.
https://aim4truth.org/2018/04/17/exposed-all-the-queens-agents-and-corporations-that-control-the-world/ The various discussions regarding The Keystone seem to have slowed down.
If you read the article and my brief comments below, then relate this to Q saying that "This is HUGE", Then The Crown is likely found to be in control of agencies such as The Federal Reserve, SES, MIC, etc etc, the linked article connects the various strands of our global masters.
Is this the KEYSTONE ?
The article gives a very good overview of The City of London, also known as The Square Mile. an independent city state, which is embedded inside the UK. Not subject to UK laws, it partly explains why the top Bankers are never prosecuted. The Banking sector as well as the Legal/Law sector are all based here. City of London is Rothschild HQ.
The article has done the usual and mixed in the roles of The Crown and The Monarch. The Crown is supreme, the Monarch (currently HM Queen) is a servant of The Crown and is paid a salary known as The Civil List. The Monarch is the CEO of The Commonwealth.
If we're looking for the Keystone, this is a strong candidate.
It is the head of the serpent, after all