www.madmaxmovies.com

One thing that surprises me between this remake and the old trilogy is that the previous Max world had a shortage of not only water, but gasoline/ammunition/food. Humungous gang used crossbows and arrows, and Humungus himself kept a case with few bullets to be used only in special situations. Papaga...

Rictus Erectus is a latin for "Mouth/Jaws upright", so based on the conceptual art + trailer, he probably had a muscle/bone deformity around the jaw area and he needs to wear that rubber strips on his face (this the trailer screen screenshot) to keep his jaw in place.