Invented by his best- and only- true friend, Kiran. They were first used between the two, to say when they needed each others help.
They would go from being green to a bright red when called, and could tell where the other person was.
However, soon after they were invented, Kiran realised how far Adrian really wanted to go with his power madness, and backed out. Destroying his own band, he ran from Adrian, hoping that one day he would be able to stop him. Adrian has never found Kiran, and never forgiven him.
Over the course of a year, Adrian changed them, turning the band into something he could use, something he could control people with.
The are sill green, but now in the shape of the ‘infinity’ sign, wrapped around a someone’s wrist. This is because once they are on, only Adrian can take them off…
The bands hold a lot of power. They can tell Adrian the whereabouts of any of his ‘Army’, and the emotions of them at the time. They have a very mild Imperious curse on them, so when someone is ‘called’ they will obey Adrian.
they turn blue if and imperious curse is used on them...
Some added features on Crouch’s one-
It renders the dark mark useless. And if Crouch tries any spells on Adrian, then they would hit, yes, but also the effects would happen to River.
(they can do other stuff as well)
Kiran has tracked Adrian, but he does not know. He plans to stop Adrian, what ever the cost…(yes, that does mean there might be a chance to defeat him…
)