Modeling is the act of using value to create the illusion of depth using shadow and shade. Michelangelo was a master of modeling in his paintings because of his skills as a sculptor. He understood how shapes looked and felt in three dimensions and was able to put this to work in paintings such as The Holy Family.
Modeling was quite similar to the models of today; the only difference being that the models were not photographed. Michelangelo spent a lot of time studying his muses and models, so he could get every single detail correct. That is why his statues and paintings are so realistic, he put an absurd amount of effort into his work, and it definitely paid off.
If you're asking what his 'role' is, to be specific the Chinese Emperor, rules China. For the Chinese he the emperor rules ' the whole world and has the power over 'everything under the sun.'"