(Throwing a wild guess out here).
Yamato appears on top of the skull and looks down on the man she used to call "Father" and declares that she's come to severe the chain that binds her to him.
For all of her life, Kaido has been this towering and imposing tyrant that dominated every aspect of her. He was in a position of absolutely power over her, and both literally and figuratively was looking down on her.
When Yamato truly rebels and finally tries to break free of the chains that binds her to him, she's the one that looks down on him.
It's an inversion of the normal relationship between them.
@KiriNigiri,
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@Weeman,
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@Marimo_420,
@Shisui_038,
@MonsterKaido.