Naruto considers Kurama as separate from himself. He knew that he would need Kurama to fight MS Sasuke:
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Sasuke doesn't consider Kurama as belonging to Naruto; neither does Naruto. However, Naruto considers Sasuke's eyes as his:
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As seen above, Sasuke comments, "This is the
Kyubi's state..."
Naruto commented, "
His new Sharingans..."
Sasuke's eyes are his own, while the bijuu will never belong to Naruto.
If we remove bijuu from Naruto he dies. If we remove eyes from Sasuke he is blind but has eyeless susanoo.
If Naruto never got Kurama then haku solo neg diff while part 2 is called Sasuke Shippuuden.