Okay, so to those who may be aware of this, I have become aware that "Mark Chandar" is the name of a character in Tom Clancy's Rainbow Six: Siege, after doing some research to see if the name has been placed anywhere. Please keep in mind that there are no parallels between the two characters whatsoever, and that I have my own reasons for naming the character in 1983, Mark Chandar. As far as the middle name, "Regal", I'm not sure if the game quoted above uses this name as well. Either way, Regal is also separate from Mark Chandar (the Mark Chandar from the Tom Clancy title).
In short, the two characters are separate, and there is no connection between them.