So, that thing gains power by absorbing strong apostles that may betray. In other words Cross is already one with that thing, or have escaped. It can use any innocent that isn't synchronized with the user to the max - general leve(?)(like Cross's gun as his true main innocent is the lady).
For a second I though that Tikki will use that cape the same way that Allen uses his xD.
I wonder what that thing did to Tikki or all noah the last time they have meet. The smile on his face was similar to one that 14 was giving Allen before awekening.