king of the castle

the king of the castle (the boss; leader; the person in charge of something) — хозяин, главный; ~ царь горы

Example 1: Jack, meet Stanly. He is the king of the castle around here. — ... Он у нас тут всем заправляет.

When a man wants to let others know that he is the boss (usually at home but not always), he might say this.

Example 2: I am the king of this castle and what I say goes. Right, right, just don’t forget to do the dishes.(WM)

[rule the roost]