Merlin watched closely as Isdis's control did its job. It didn't work like any normal magic, but was far stranger. She didn't directly control the star, but highjacked Eris's divine magic with her own will to influence the sun. Isdis's divine magic worked like an imposter, taking others' will and then mimicking it to take their place.
To the sun, Isdis looked no different than Eris. Control didn't just give the power to dominate and order things and people around, but it gave Isdis the ability to influence, mimic, and trick anyone into following her will. When Isdis commands someone to do her bidding, they aren't seeing her, but someone they respect, care about, or love.
