Design documents revealed during the recent Rockman Unite event held in Japan to commemorate the 30th anniversary of Mega Man X gives some insight into a few of the game's characters.
As reported by Rockman Corner (a resource for Mega Man related news), the original document shows how far back the Mega Man X backstory was established.
A translation of the document provided by Twitter user @Kobun20 illustrates an official character relationship chart, mapping out the connection each character had with one another.