I am guessing the name of the seven emperor demon lord is not the person from the mythos but just a title that has been passed down. That or they want to appear threatening since their actual appearance is bland or weak
@PotatoZero It is true, but casted has been used informally for diferent things, so while is incorrect in the modern english grammar point, is not something unheard of.
Then again English is not my first language so I don't really know that much.