I thought again. The pratice of Asubha meditation with the sight of a dead body or other disgusting think can destroys Kama ragā and lead one at least to anagami phala. After that if this anagami continue to focus to the real signification (who mean all type of body even a brahma body is asubha) he will destroys rupa and arupa ragā. He will eventually becomes arahant by removing the others fetters. An arahant reject any kind of body and see asubha nature in all type of body presents in the 31 plans.
Asubha first level : removing kama ragā lead to anagami state, by the sight of disgusting nature in the body of a being in kāma Loka and also understand the incapacity to maintain our body beautiful and optimal to enjoy sensual pleasure. (For example the sex is just a fluid exchange) We will becomes a dead body eventually and we will not enjoy anymore the sensual pleasure. It is fruitless to craving the sensual pleasure. We can fall in the apayas if we are too attach to them. We would really have disgusting bodies in this worlds. For example a peta have a ugly stinky body . An niraya being can have the belly open with the torture and he or she have all type of ugliness. We see in the animal world the worm who born in the trash or all kind of bugs. A deva becomes suddenly old and lost all his beauty near death (in the deva world a old deva is the most disgusting sight). A human becomes old, stinky and becomes a dead body. Even when we are alive we eat and go to the bathroom after, we have all type of disease or disability who lead to ugliness. We had blood and organ.We will inevitably had a disgusting body if we don’t see the danger in sensual pleasure.
Asubha second level : removing arupa ragā and rupa raga. This the most and important. See the danger of all type of body in the Samsarā. A brahma as beautiful as he is will have to disappear and lose his brightness. He can eventually reborn in the apayas where the real ugliness are. (Of courses a anagami will reborn in a pure land but this worlds are not eternals) This example is more for the anariya brahma. Generates a body bring all kind of suffering and perpetuates the cycle of Samsarā. To no longer desire any type of body is happiness.
(Sorry for the repetitions i just want to be sure that anyone can understand what i want to says.)