This is the one true religion and way of life. Ethan does not believe this, which makes him an infidel, so he does indeed believe in him but he doesn't believe is as well and believing again etc. The rival is MervueMeringue who believes in Arceusfan and he also believes MervueMeringue making him an infidel which means he believes in Arceusfan which makes him a true believer etc.