He's all about getting results
Like Trump, Set knows how to get into his opponent's heads: intimidation. When the movie opens, the god Osiris (Bryan Brown) rules over Egypt with a mix of kindness, sweeping hand gestures, and a very clear height advantage. Getting late in god years, he's ready to give away his kingdom to his son Horus, the god of air played with a charming brattiness by Nikolaj Coster-Waldau from Game of Thrones. But, then Butler's Set, the much younger (and more Scottish!?) brother of Osiris, shows up and kills Osiris, snatches out one of Horus's eyes, and basically takes over Egypt. The guy doesn't even have to caucus.
If you've been watching the primaries play out in South Carolina, Nevada, and New Hampshire, this should be familiar. Horus, like Marco Rubio, Jed Bush, or any other Republican establishment hopeful, thought he had this all wrapped up. Then this brutish goon showed up and started pushing everyone around. And, man, does Set have a Trump-like ego. At one point one of his servants says, "You look glorious," and he grins before saying, "I know!"