Every time you complete a pantheon with a binding, one of the circles around the door lights up. Once you complete a total of 8 bindings (e.g. all four bindings of the first two, easiest pantheons. Can be done in 2 very hard runs or 8 moderately hard runs, if you have the time), you can enter the room to gain a permanent advantage on all future paththeons in the form of two lifeblood masks in each of the hotspring rooms. After that, every time you complete 4 more bindings, you get 1 extra lifeblood mask during the pantheons up to a maximum of 4 (judging by the total number of circles around the door). Hope this Helps!