Catholicism and Protestantism believe in the same god and are different factions of the same religion.
The content of the Islamic Koran is very similar to the Bible, even the details of the story and the names of the characters are similar, but they are different in terms of words and expressions, and almost the same in concept. So in religion, scholars believe that this religion and Christianity believe in the same god, that is, Allah, Allah, that is, God.
Why do you say that? Because Christianity believes that "God" is the only true God and the only master in the universe. Islam also believes that "Allah" is the only true God and the only master of the universe. If there is such a single true god in the world, don't their two religions speak of the same true god? It's just that people of two religions give different names to the same god.
So three religions believe in the same god. Who do you think is the boss? Just the same god.