#2 Luke Harper aka Brodie Lee

The man formerly known as Luke Harper in WWE is very possibly debuting in AEW very soon. If it isn't the upcoming Dynamite episode, it could be sometime this month as his 90-day no-compete clause ends on March 08, 2020. With that being said, him possibly being the so-called leader of The Dark Order has a high probability rate.
The connection is quite obvious. Standing at 6' 5", he would come across as a legitimate villain and be a valued addition to the group. His time with the Wyatt Family certainly has created an image that is hard to deny, that of a dark soul who is capable of ultimate destruction.
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Dustin Rhodes even spoke of the possibility of Harper being in AEW and said:
"He can help people. He can take them to new highs and he can get them there and at the same time get himself over in a company that will allow him to do so."
The possibility of him being the leader of The Dark Order is certainly something to think about.