They're both clones of Big Boss, part of a program to create
the ultimate soldier.
How does General Ross's desire to develop
the ultimate soldier impact his judgment?
To recap: Russell is trained from birth to be
the ultimate soldier — cold, emotionless, ruthless, to follow orders without questioning, etc..
Call of Duty is a good example, portraying you as
the ultimate soldier capable of mowing down the enemy with abandon.
The lone wolf thing is a stretch for realism but as a game it was pretty cool being the elite Marine and
ultimate soldier.