It should be noted that Arturia has run marked on her back, after careful inspection it has been noted that the run on her back is, in fact, a seal that subjugates her to Guy's servitude.
Isha herself is known to have the same run on her back, while Guy holds runes on both his hands marking him as their master.
After interrogating both women it has been noted that according to both women the runes provide telepathic communication between the three of them.
They allow both women to know when Guy is in danger and help provide energy to both of them when in severe danger.
It should be noted that when the Rune's were removed Arturia did not take it kindly...This is the reason that no one has ever tried to remove them again... Please read carefully...
...Arturia broke her restraints after a rief amount of fighting proceeded to make the same runes that had been removed from her and Isha on every person that had any form of significant rank inside the research facility.
Isha was for the first time recorded far more cruel than Arturia, she did not forgive anyone, by the time she was done, everyone she managed to get her hands on was covered in runic engagements.
It's still not known if the runes work as some form of restraint considering that both women continued their attack by marking several designs on the facilities walls, ceiling, and floors.
It remains one of the most secure buildings on the planet, no one that has any ill intentions can so much as get near the building.