Board Thread:Theories and Speculation/@comment-45444155-20200806213256/@comment-1512913-20200809201848

In Jugo's clan, their bodies passively absorb natural energy and then there's the natural 'curse mark', which I believe to be their bodily fluids reacting, but I believe the transformation is caused not by natural energy alone, but by Senjutsu chakra, otherwise they would be transformed constantly. Imo, Sage Mode, is simply put nothing but name for the enhanced state caused by Senjutsu chakra. That being, even Curse Mark users are technically in Sage Mode, but since the manga itself distinguishes them, calling Curse Mark an imitation, so should we, but you get the point.