As the thead title says, the Greek bodyguards have an upkeep cost in addition to the usual 200 per turn family member wage. Other factional bodyguards dont have any upkeep. I think this is because they are set up as having Spartan hoplites as their bodyguard which are a regular unit with 774 upkeep per turn, rather than using a general's bodyguard unit which dont have any upkeep.