After years of preparing her group, Stella has taken certain precautions within her group.
One of them of course was to take care of spies and possible traitors. It helped that her group was the only one outside of Sword's circle, so most already tended to go to them.
And the Colosseum environment did not leave much space for spies, still, one or two might be sent from one of the other leaders. Most of which are dead.
Because of her ambitions, Stella couldn't leave any space for possible spies, so she kept a lot of things for herself early on.
It took a while but she managed to develop an eye on who could be trusted and who couldn't. Enough years of practice and she was sure she had gathered together a pretty safe group.
One of the reasons she trusted Mares so quickly was exactly because of her perception and it had been proven right on enough occasions by now.
