Styx's collar was a gift to Lilith from Echidna that allows her to control him. It's primary function is to prevent him from turning to stone after drinking water from the River Styx. This functions as a protection and control mechanism for Lilith.
Heel A leash of flame extends from Lilith's hand to the collar, allowing her to tether Styx when he is disobeying.
Release The collar clasp immediately opens, releasing the collar from around Styx's neck.